About $43 billion has been wiped from Australia's share market, as oil prices surged after fighting between the US and Iran loomed over hopes of a peace deal.
The S&P/ASX200 fell 133.7 points on Friday, down 1.51 per cent, to 8,744.4, as the broader All Ordinaries lost 126.5 points, or 1.39 per cent, to 8,980.5.
It was the exchange's worst day since mid-March, with 10 of 11 local sectors tumbling after the US and Iran accused each other of breaking an already fragile one-month ceasefire.
US President Donald Trump has claimed negotiations with Iran to end the conflict and reopen the Hormuz Strait - a choke point for a fifth of global oil and gas supplies - remained on track.
The Australian dollar is buying 72.24 US cents, down from 72.50 US cents on Friday at 5pm, trading near four-year highs since the Reserve Bank hiked the cash interest rate to 4.35 per cent on Tuesday.