In an opinion piece in The Australian on Thursday, the former defence minister said that before the federal election in May, Defence was investigating buying two Virginia-class nuclear-powered submarines from the US by 2030.

The arrival of the submarines would be at least 10 years ahead of schedule, compared with being built in Australia.

Mr Dutton said he anticipated the government would have been ready to make an announcement on which submarine class to go with as soon as July.

He said he always suspected Labor was "never truly supportive" of the trilateral agreement.

"I really worry now that Labor is walking away from AUKUS, from the submarine deal, and that is clearly not in our national interest," Mr Dutton told 2GB.

In March, Mr Dutton said there would be an announcement "within the next couple of months about which boat we are going with, what we can do in the interim", which would have put the decision well ahead of the initial 18-month consultation period, due to wrap up in early 2023.

Defence Minister Richard Marles labelled Mr Dutton's most recent comments "rank politics" that flew in the face of his previous pledge to work with the government.

"This outburst today, from someone so recently in the chair, is damaging to Australia's national interest," he told AAP.

"The comments are loose and undermine the AUKUS agreement.

"The coalition's ability to talk tough and beat their chest without delivering is only being highlighted whilst they're in opposition."

Mr Marles previously told the Sydney Morning Herald the projection for delivery when the former government left office was likely to be in the mid-2040s.

"We need to look at how we bridge the gap. That's all I can say. And my mind is open about how we do that," he said.

Mr Marles said the government had not yet made a decision on the preferred submarine, with "all options on the table".

He will visit Singapore on Friday for the Shangri-La Dialogue, to discuss security with 30 of his Indo-Pacific counterparts.

Mr Dutton wrote that the American submarine was the best option to prevent a capability gap following the retirement of the Collins-class submarines from 2038.

"I believed it possible to negotiate with the Americans to acquire, say, the first two submarines off the production line out of Connecticut," he wrote.

"This wouldn't mean waiting until 2038 for the first submarine to be built here in Australia.

"We would have our first two subs this decade. I had formed a judgment the Americans would have facilitated exactly that."

Mr Dutton said Australia needed nuclear-powered boats because "diesel-electric submarines would not be able to compete against the Chinese in the South China Sea beyond 2035".

Earlier this week, it was revealed a Chinese military fighter jet dangerously intercepted an RAAF plane conducting routine surveillance in international airspace on May 26.

Prime Minister Anthony Albanese said the government would stand up for Australia's national interest and work to de-escalate tensions in the region.

"It's not in anyone's interests for instances like this to occur," he told KIIS radio.

Australian Associated Press