Joe Courtney

The senior US Democrat on a Congressional committee overseeing AUKUS says US President Donald Trump's repeated criticism of Australia is "unfair" and causing harm to the US with its allies.

"I think it's a very unfair criticism by the president," Joe Courtney told 7.30.

Mr Trump said on two occasions he was "not happy" with Australia's position on the war in Iran, saying Australia had declined a request to join US efforts in the Strait of Hormuz, something the Albanese government has denied.

Mr Courtney, who is also the founder and co-chair of the bipartisan Friends of Australia Caucus, says Mr Trump's attitude is damaging.

Asked whether he was surprised to hear that members of the Coalition — traditionally unambiguous supporters of the US — were being critical of Mr Trump's comments, Mr Courtney said: "I'm not surprised to hear that unfortunately, because we obviously follow what's going on in Australia … and we're not blind to the fact that this harm and damage that's being done is affecting public opinion."

'Blind eye' to the legality of war

Mr Courtney has been a persistent critic of the war in Iran, calling for Congressional oversight of the deployment of troops to the Middle East and the Gulf.

He also believes Mr Trump's inconsistent public statements are a problem.

"We can't just keep giving him [President Trump] free reign to conduct this war, Mr Courtney said.

"He's changed his mind almost on a daily basis about whether or not we've won, we've lost; whether or not it's hours away or days away for a settlement. I mean, we clearly are not at that place right now.

Mr Courtney says Americans are currently experiencing the negative consequences of the war in terms of fuel and fertiliser prices, and seeing the military overextended.

"People [are] watching our military getting really stretched to the breaking point in terms of deployments way beyond normal operations for both the Navy and also National Guard forces."

He says the Democrats will push for another vote in the House this week to seek authorisation for the use of force in Iran.

"The last time we had a vote in the House, which was about a week or so ago, the vote failed by one vote," Mr Courtney said.

"Now that we've hit the 60-day threshold of the conflict, we are going to pass that milestone tomorrow."

More money for AUKUS subs?

Mr Courtney made the comments shortly after King Charles III addressed the US Congress in a speech where the British monarch praised the trilateral AUKUS alliance and submarine pact.

"I was very pleased to see members from both sides of the aisle stand up and actually make a point of applauding the King's comment," Mr Courtney said.

He said AUKUS would survive the current administration in Washington.

"It's going to be something that will rise above this time that we're living in right now with the Trump administration."

The production of submarines in the US must increase above two per year to be able to meet AUKUS requirements. It currently sits at 1.1.

Mr Courtney says AUKUS will meet its delivery deadlines, beginning with a Virginia class submarine in 2032.

However, he also signalled that although Australia's financial contribution to US submarine production was adequate for now, it may have to increase.

"I don't think the $3 billion number, which was in the optimal pathway, is the 10 commandments. I think that as this enterprise unfolds, there may be a rationale for Australia to participate more," Mr Courtney said.

"There's factors that go into shipbuilding from one year to the next in terms of just simple things like inflation that sometimes change cost estimates."