Emergency crews were called to Viva Energy Group's Geelong refinery at about 11pm local time following reports of explosions.
No injuries have been reported, but the blaze continues and authorities said smoke could impact some nearby areas.
The facility, about 40 miles southwest of Melbourne, supplies more than half of Victoria's fuel and 10% of the country's.
It produces up to 120,000 barrels of oil per day and employs more than 1,100 people.
Chris Bowen, Australia's energy minister, said the fire was not yet under control and admitted "there's still some way to go".
He told Channel Nine: "This is not a positive development, but obviously there's a long way to go in terms of working out just what the impact is."
Mr Bowen added that the incident "appears to be an accident at this point".
Jet fuel and diesel can still be produced at reduced levels as a safety precaution, but Mr Bowen warned petrol production could be affected.
It comes as the country seeks to strengthen its own fuel supply to help mitigate the disruption and soaring global oil prices resulting from Iran's closure of the Strait of Hormuz, which has triggered panic buying at Australia's petrol pumps.
Last month, Australian Prime Minister Anthony Albanese announced temporary relief measures, which included halving the fuel excise and suspending the heavy road user charge for three months, in an attempt to help households cope with a surge in costs driven by the Iran war.
'A huge shock'
Geelong Mayor Stretch Kontelj said the incident was "unprecedented" - telling ABC: "I've spoken to management there this morning and needless to say, this has been a huge shock and has rocked them.
"The fire is still burning and will have to just burn out. Because of the intensity, it was difficult for the fire units to do much other than to watch."
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Viva Energy CEO Scott Wyatt insisted the main focus was to extinguish the blaze, which he said had impacted operations at two units.
Mr Wyatt said: "All the other units are still operating and still in production but they are at minimum rates to maintain safety across the site.
"We'll only start increasing production again once we're confident that we can do that safely."
Diana Sanders was given at least 14 shots of tequila over a nine-hour period in January 2024 while aboard the Carnival Radiance.
Soon after leaving one of the ship's bars, she experienced a fall that left her with a concussion, headaches, back injuries and bruising.
The 45-year-old was later found unconscious in a crew-only area, with missing surveillance video from the night shown in court.
A jury in Miami has now ruled in the 45-year-old nurse's favour after concluding that the company has acted negligently.
Her attorney Spencer Aronfeld said: "Taking on a corporate giant like Carnival is a massive undertaking, and I have enormous respect for my client's resilience.
"This case highlights the inherent danger of all-inclusive drink packages, which encourage excessive consumption and pressure underpaid servers to prioritise tips over safety."
During the trial, Mr Aronfeld had argued the cruise ship's bartenders should have stopped serving her once she became visibility intoxicated.
He also alleged Carnival "deliberately designs its vessels … to ensure that there are alcohol serving stations in every nook and cranny of the ship" to maximise profits.
The $300,000 reward is $250,000 more than had been requested during the trial.
Mr Aronfeld told Sky's US partner NBC: "Proving the over-service of alcohol is often difficult, as many people believe individuals should be solely responsible for their own consumption.
"Diana, admitted her personal responsibility; however, the core issue was Carnival's refusal to accept any corporate responsibility for serving someone who was clearly intoxicated."
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Carnival Cruise Line has said it respectfully disagrees with the verdict, and believes there are grounds for a new trial and appeal.
Its lawyers had argued that there were no allegations of Ms Sanders "stumbling, sleeping at a bar, slurring her words or exhibiting any other intoxicated-like behaviours".
In a separate case that is still ongoing, the fiancée of a man who died on a cruise ship has filed a wrongful death lawsuit against Royal Caribbean.
It alleges the company negligently served him 33 alcoholic drinks and was liable after crew members tackled him to the ground and stood on him with their full body weight.
A survey by the Economist Educational Foundation found that 22% of 15 to 17-year-olds had stopped themselves sharing political opinions because they were worried about criticism, along with 20% of 10 to 14-year-olds.
Nearly one in four of the 4,000 students aged between 10 and 17 who took part in the survey said they have been asked to stop voicing their political views at school.
The results also showed that 44% of 15 to 17-year-olds said they would not feel ready to vote in the next election.
It comes after the government introduced plans last year to lower the voting age to 16, enabling up to 9.5 million more people to have their say at the next general election.
The Economist Educational Foundation's chief growth officer, Tiffany Smyly, said the fear of being cancelled could push teenagers to online "fringe" communities where their views could become more extreme.
She warned: "If teenagers are worried about being cancelled, then they are not going to be sharing their viewpoints at school or with friends.
"Instead, they are likely to go into chat rooms or forums that do allow them to share a fringe opinion, and that might be where their views become more extreme.
"We need to channel young people's political curiosity in more positive ways."
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The survey found the cost of living crisis and healthcare are the main concerns for younger people.
Those who took part were more likely to say they were curious about politics than uninterested in it - and more than two-thirds of 15 to 17-year-olds admitted they would feel more confident voting if they knew more about different political policies.
Flora Letanka, chief executive of the Economist Educational Foundation, called for more opportunities for young people to openly discuss the topics that matter to them.
She added: "We need to ensure young people are given the chance to think critically about what's going on in the world, to explore different perspectives, and see the real impact of political decisions on the people around them."
As companies grapple with surging energy prices caused by the Middle East conflict, ministers said a further 3,000 businesses were to benefit from the British Industrial Competitiveness Scheme (BICS).
It is now expected that 10,000 manufacturers will get a 15%-25% bill reduction through being spared contributions to three existing policy cost elements, including the renewables obligation and feed-in tariffs.
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The Department for Business and Trade (DBT) said qualifying companies - all intensive users of power - would also secure a one-off payment next year to make up for the BICS scheme not being in place during 2026.
As its name suggests, BICS is aimed at bolstering UK factory competitiveness as the country has long suffered the highest industrial energy prices in the developed world.
That burden has been the major force behind the gradual decline in UK manufacturing across sectors such as steel and chemicals, leaving the country more exposed to imports to meet its needs.
BICS was the first major plank of the government's industrial strategy outlined last June when bills for businesses and households alike continued to reflect growing policy costs, alongside a stubbornly high wholesale element left by Russia's invasion of Ukraine.
The Iran war means hard-pressed companies are already experiencing higher bills in many cases, as there is no price cap to protect them from the surge in oil and natural gas prices.
Chancellor Rachel Reeves, who is in Washington DC for the International Monetary Fund spring meetings, agreed the additional but still-delayed support after warning over the impact of the war on inflation and economic growth.
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"This government has the right plan for the economy: backing British industry, cutting electricity costs and building a stronger, more resilient future", she said.
"Today's announcement will cut energy bills for over 10,000 manufacturers, helping businesses to compete, win and create good jobs across the country, and to deliver our modern industrial strategy."
But Stephen Phipson, chief executive of the manufacturers' lobby group Make UK, said in response: "While this announcement acknowledges the problem of high UK industrial energy costs, it doesn't provide the immediate solution to the critical cost pressures companies are facing right now.
"Manufacturers are staring down the barrel of huge increases in their energy bills this month as they renegotiate their energy contracts and, when combined with other cost increases, many simply can't wait until 2027 for relief.
"Failure to provide help now risks substantial job losses and further deindustrialisation of a sector vital for our national security and resilience."
The incident in Finchley is being treated as an antisemitic hate crime, police said.
Officers from the Met's North West Area Command Unit arrested a 47-year-old woman at an address in Watford on suspicion of arson endangering life on Wednesday afternoon.
They later also arrested a 46-year-old man in the Watford area on suspicion of arson endangering life.
Both suspects remain in police custody.
CCTV obtained by police showed two people, who were wearing dark clothing and balaclavas, approaching the synagogue in Fallow Court Avenue shortly after midnight on Wednesday and throwing two bottles, suspected to contain petrol, and a brick at the building.
Neither bottle ignited, and no damage was reported. There were no injuries.
The matter was reported by staff to police at 8.30am.
Detective Chief Superintendent Luke Williams, who leads policing in the area, said: "I hope the swift action by officers today to identify and arrest two people provides some reassurance and demonstrates how seriously we take attacks of this nature.
"However, we understand the significant concern the Jewish community will feel at another incident so soon after the arson attack on four ambulances in Golders Green."
Four men and a 17-year-old boy have been arrested in connection with an arson attack on a Jewish volunteer ambulance service in Golders Green last month. Two were released pending further enquiries, police said.
"There is no suggestion the matter in Finchley and the incident in Golders Green, for which three people have been charged, are linked," DCS Williams said.
DCS Williams said patrols would be increased in the Finchley area.
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Cantor Zoe Jacobs, senior clergy at the Finchley Reform Synagogue, said the Jewish community would "not be deterred by these cowardly acts".
"Instead, we will continue to prioritise building bridges across the wider Barnet community," she said.
Police could be seen working at the scene on Wednesday.
One officer was photographed outside the synagogue beside a bottle with a blue rag in the top.
Mayor of London Sadiq Khan said: "I'm grateful to the Met Police for their swift response to the appalling attempted arson attack at Finchley Reform Synagogue overnight.
"The incident is being treated as an antisemitic hate crime, and there is an increased police presence in place in the local area."
Labour MP for Finchley and Golders Green, Sarah Sackman, said such incidents could not be allowed to become the "new normal" in Britain.
In a letter handed out to residents on Wednesday, Ms Sackman said: "I understand this will be concerning to local residents. I want to reassure you that there is a strong police presence and investigations are ongoing."