Corio Sits Next to Victoria's Only Refinery and Pays 5 Cents Above the State Average
There's a stretch of the Princes Highway north of Geelong where you can watch fuel being made. Cracking towers, flare stacks, steam, the lot. The refinery at Corio has been turning crude oil into petrol and diesel since 1954, and it is now one of only two still running in this country.
You'd think the servos across the road would be the cheapest in Victoria. They aren't.
At 8:13am AEST on Saturday 1st Aug 2026, diesel prices across the six Corio sites we track averaged 243.1 cents a litre, up from 232.8 the day before. A 10.3 cent move overnight, in a suburb where the stuff is made within sight of the bowser. The Victorian average across 836 stations sat at 238.0 and eased a touch on the day. So Corio drivers are running about 5 cents above their own state, and level with Canberra, a city roughly 500km from the nearest refinery.
The reason has nothing to do with the towers.
Refineries don't set the price on your driveway
Australian wholesale fuel is priced off the Singapore benchmark, not off what it costs to make a litre at Corio. Import parity pricing, they call it. A refiner sells locally made diesel at roughly what a Victorian buyer would pay to bring a cargo in from overseas instead. Whether that litre came out of a tower beside the highway or off a tanker berthed at Melbourne, the reference price barely moves. The same logic drives unleaded petrol prices, which is why nobody in Geelong has ever had a hometown discount.
The refinery is still worth having. Its value is national, supply security in a country that imports nearly everything else it burns, and that argument stands up on its own merits. It has simply never shown up on a board price in Corio.
Going back a couple of decades
In 2003 Australia had eight working refineries. Then they started falling over. Port Stanvac in South Australia wound down, Clyde in western Sydney closed in 2012, Kurnell followed in 2014 and became an import terminal, Bulwer Island in Brisbane shut in 2015, and in 2021 both Altona and Kwinana stopped refining within months of each other.
Two survived: Corio, and the Lytton plant in Brisbane. Both are still going partly because Canberra decided in 2021 that letting the count reach zero was a risk worth paying to avoid. The federal fuel security package hands the operators a production payment when refining margins turn bad, and it runs into the next decade. Alongside it sits a minimum stockholding obligation, which forces refiners and importers to keep a floor of fuel physically inside the country.
Industry contacts tell me the payment has done the job it was given, which was keeping two plants alive. Making your fill cheaper was never on the list.
What the rest of the country did overnight
New South Wales diesel added 10.4 cents to average 239.3 across 1,351 sites, the biggest state move on the board. Tasmania climbed 7.7 to 239.6. Western Australia went the other way, easing 1.3 to 240.1. Victoria's small dip leaves it the cheapest mainland average for diesel at 238.0, while the Northern Territory sits in its own universe at 279.2.
Some of that rise is servos positioning ahead of Monday's excise change, which I wrote about on Wednesday. Some of it is ordinary weekend timing. And a one day state average swings on which sites happened to report, so don't read too much into any single morning. Price trends across a fortnight will tell you a good deal more.
The gap that actually costs you money
To put this in perspective: the spread inside one suburb is usually wider than the gap between states. In Reservoir, on the northern edge of Melbourne, diesel ran from 222.2 to 241.9 this morning. Same suburb, 19.7 cents apart. Statewide, the cheapest Victorian diesel reported was 192.9.
Fill a 70 litre ute at the wrong end of a spread like Reservoir's and you've handed over about $14 for nothing. Do that weekly and it's a decent night out by Christmas.
Before Monday, check the boards either side of your usual servo instead of pulling into it out of habit. Top up over the weekend if you're running low, because the excise step lands early next week. And if you're driving through Corio expecting a refinery bargain, save yourself the disappointment. Buy where the numbers are good, not where the towers are.
Six of the eight refineries running in 2003 are gone. The two that are left are a national insurance policy rather than a local discount, which is why Monday's excise step will land on the boards in Corio exactly as it lands everywhere else. The ships keep arriving either way.
