The Australian sharemarket has made a bright start to the session as a tentative deal to extend the ceasefire in the war with Iran by 60 days helped lift the market and rein in oil prices.

The Australian sharemarket opened lower after the US military said it carried out “self-defence” strikes in southern Iran, triggering doubts about an imminent end to the war.

Global stocks rose to record highs as crude oil fell after officials signalled the US was nearing a deal with Iran to reopen the Strait of Hormuz and restore oil flows.