The two countries have confirmed plans to cease hostilities and reopen the Strait of Hormuz, which before the latest flare-up in February carried about 20 per cent of the world's oil.
Kylie Moore-Gilbert, an expert on Middle Eastern politics who spent more than two years in an Iranian prison, said the pause in fighting would likely be temporary because of unaddressed sticking points.
The agreement failed to deal with Tehran's ambitions to build nuclear weapons, its use of proxies in the region, its missile program or human rights abuses, Dr Moore-Gilbert said.
"Every single reason cited for this war by the Trump administration ... has not been addressed," she told AAP.
"All those sticking points remain, and we can expect that the Islamic Republic will continue in its intransigence and resist coming to any kind of arrangement or agreement on those points.
"This is just kicking the can down the road to the next conflict."
The Australian government has welcomed the peace deal as an important step to reduce pressure on the global economy after the world's largest oil shock.
"We are pleased the agreement between the US and Iran includes steps towards reopening the Strait of Hormuz and the restoration of freedom of navigation," Prime Minister Anthony Albanese and Foreign Minister Penny Wong said in a joint statement.
"While full recovery will take time, restoring this vital trade corridor is essential to easing pressure on energy prices and economises, including in our region."
More work was needed to secure a "durable and lasting peace", the pair said, including Iran addressing longstanding concerns about its nuclear program.
At various points in the conflict, the US and Iran have announced the closure of the Strait of Hormuz, sending many countries including Australia scrambling to find new sources of fuel.
Dr Moore-Gilbert said Australia was effectively a bystander in the negotiations, with little say in what happened next.
"Whatever statement our government makes, neither side's going to pay any attention whatsoever to us or what we think," she said.
US President Donald Trump took to social media to announce the peace deal after four months of on-and-off fighting in the Middle East, triggered by US and Israeli strikes against Iran in late February.
"The deal with the Islamic Republic of Iran is now complete. Congratulations to all!" he posted on his platform Truth Social.
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