A late night fire at the Viva Energy Refinery in Corio, north of Geelong, is expected to affect fuel production, adding to concerns about supply as conflict involving Iran continues to unsettle global markets.

Fire Rescue Victoria was called to the site just after 11pm on Wednesday following reports of multiple explosions in the plant’s “mogas” area, a section linked to making “high octane fuels”. FRV assistant chief fire officer Michael McGuinness said significant “liquid hydrocarbon and gases” were believed to have fed the blaze. “This is a quite dangerous fire. We are dealing with highly-flammable materials, both liquids and gases,” he said on Thursday morning.

Energy Minister Chris Bowen said the incident is set to have “an impact on production” of Australia’s fuel. “At this point, production of jet fuel and diesel is continuing at the refinery at reduced levels for safety reasons, as a precaution.”

A worker and AMWU member, Tony Hines, told Sunrise the facility could be out of works for “weeks at a minimum”.

The Geelong refinery is one of only two operating in Australia after six of the nation’s original eight domestic refineries shut over the past two decades, leaving Ampol’s Lytton refinery in Brisbane and Viva Energy’s Geelong plant. The Geelong facility supplies about 10 per cent of Australia’s fuel, around half of Victoria’s fuel, and can process up to 120,000 barrels of oil a day.

Authorities said the emergency was continuing but public safety was not at risk. “The fire is still being fought by fire fighters but there is no threat to the public,” the CFA said. “Smoke may still impact the area between Plantation Road and Cox Road, and between Bacchus Marsh Road and the water front.”

No injuries have been reported. Victoria Police said an investigation will begin into what caused the incident.