Viva Energy, which owns the oil refinery in Geelong, alongside a 1300-strong network of petrol stations across the country, reported a bottom line first-half net profit jump of 331.3 per to $452 million.
The result was driven by runaway fuel sales at higher margins on the back of supply constraints caused by the Middle East crisis, which has closed the Strait of Hormuz, a vital global shipping lane.
Net profit on a replacement cost basis - which excludes the impact of oil prices on inventories - soared by almost 500 per cent to $371.1 million in the six months ended June 30.
This was its highest underlying first-half result, with all three business units reporting significant growth as total fuel sales hit 8490 megalitres.
Viva Energy chief executive Scott Wyatt said the company - which operates one of two onshore refineries, with the other owned by Ampol - has identified opportunities in the federal government's recently announced fuel security measures.
"Right now, we are heavily engaged with the government on policy development to provide long-term investment for the refining sector, which we expect to provide more certain returns than the current fuel security services payment," he told an earnings briefing on Tuesday.
The Labor government wants to set up a one-billion-litre strategic fuel reserve, increase industry storage rules to ensure at least 50 days of supply and support the two refineries, one of which is in Brisbane.
In April, a major fire broke out at Viva's facility in the Geelong suburb of Corio, affecting its alkylation processing unit, which turns low-value gases into a high-value, high-octane, clean-burning liquid called alkylate for premium petrol.
The broader facility is back to 90 per cent capacity, but full production remains a way off until the unit is replaced.
"We are assessing technology solutions and will work with our insurers to determine the best way forward over the coming months," Mr Wyatt said.
"It's a bit of a work in progress."
Viva's retail arm, which includes the petrol stations and more than 900 convenience stores, had a strong half with underlying earnings soaring 86.4 per cent to $138.7 million, mostly due to fuel sales under the Shell, OTR Liberty and Reddy Express brands.
In the past, Viva has complained about the impact of the rising illegal tobacco trade on its business, but says that's waning as authorities take action against suppliers.
For the half, tobacco sales were down by almost 17 per cent year-on-year, but flat compared to the second half of 2025.
The commercial and industrial business, which mainly sells bulk fuels and lubricants to the mining, aviation and other heavy fuel-using industries, lifted earnings by 28 per cent to $305.4 million.
And the energy and infrastructure division, which anchors the Geelong refinery along with fuel import terminals, storage depots and pipelines, enjoyed an incredible jump of almost 2000 per cent to $353.7 million.
That was due to the stronger refining margins on the back of the war.
Shares in Viva, which will pay an interim dividend of 7.73 cents, fell 1.2 per cent to $2.82.
