The nation's top military officer has pushed back on suggestions Australia has not sent a Navy ship to the Middle East because of its ageing fleet, arguing it was more a question of where the defence force should focus its efforts.
"I am very confident we could deploy a ship into that environment if the government was to make a decision to do so," Admiral David Johnston told journalists at a briefing in Canberra on Thursday.
"I have no hesitation in our ability to work in a Strait of Hormuz-type role.
"But perhaps what is an at least as important question is: where do our priorities lie?"
The opposition and some defence analysts have suggested Australia has not sent a ship because it doesn't have the capacity to do so.
But Defence Minister Richard Marles said that wasn't correct.
"We have capability, and that's not the issue," he told ABC Radio on Friday.
"We still have significant roles to play in the Indo-Pacific, which is where the bulk of our naval effort goes," Mr Marles said.
"All of those issues don't go away."
Iran has reportedly said it will begin charging a $1-a-barrel toll for oil passing through the Strait of Hormuz, to be paid in cryptocurrency or Chinese yuan.
Around one-fifth of the world's oil passed through the strait before the start of the war between Iran, the US and Israel.
US President Donald Trump took aim at the reported toll, urging Tehran to reverse course.
"There are reports that Iran is charging fees to tankers going through the Hormuz Strait - They better not be and, if they are, they better stop now!" he said in a post on his platform Truth Social.
Former prime minister Tony Abbott said Australia was betraying its values and letting down the US by not sending troops the Middle East.
"What is the point of having armed forces if they're not to be used to support our allies in a just cause?" he wrote in an opinion piece for the Daily Telegraph.
Greens Senator David Shoebridge said Australia should be focused on securing peace in the region and should not get involved in trying to keep the strait open.
"There's no conceivable way in which Australia's military contribution would assist in keeping the Strait of Hormuz open. That is not our job. We didn't create this crisis," he told ABC Radio.
