Australians could be paying $1 a litre more for petrol if a key oil shipping route near Iran remains closed for up to three months, according to Australian economists. The Strait of Hormuz — the shipping lane on Iran's southern border through which about 20 per cent of the world's oil and gas is shipped — has been effectively closed as Iran retaliates against the US-Israeli strikes. Iran has threatened to fire on any ship trying to pass the key waterway, according to Iranian media reports and on Monday a Revolutionary Guards official said a fuel tanker was burning in the Strait after being hit by two drones. The US-Israeli war with Iran has sent oil prices surging for a third consecutive day — on Monday prices spiked as much as 13 per cent to their highest since January 2025. Economists at Westpac warn the longer the conflict goes on, the worse the effects on the Australian economy and consumer hip-pockets will be.