The UK’s submarines are the best in the world, Downing Street has said after a senior Australian MP questioned their suitability ahead of a major defence deal.

The Aukus pact involving the Australia, the UK and US will see the Canberra government procure nuclear-powered submarines.

Australian opposition leader and former defence minister Peter Dutton argued against choosing British boats for the new fleet, instead backing an American model.

“The beauty in my mind with the American model, of the Virginia class, was that it was a proven design, it gave us interoperability with the Americans and there will be more American subs in the Indo-Pacific than there will be British submarines,” he told reporters.

“I worry that if the government has taken a decision to go for a cheaper design it will delay the delivery of those submarines.”

Reports have suggested Joe Biden, Rishi Sunak and Australia’s Anthony Albanese could meet in Washington this month to announce further details on the Aukus project.

In Westminster, the Prime Minister’s official spokesman told reporters: “I think through our world-leading Aukus programme we have established an excellent relationship both with the Australian government and the US government.

“There is more work to do and more to say on the Aukus programme that I’m not going to pre-empt.”

The UK “is leading the way in submarine development” and “we are very confident in our shipbuilding programme and its strength, not just in the UK but worldwide”, he said.

Asked whether British submarines were the best in the world, the spokesman said: “Of course.”

The UK hopes that Aukus will result in work for British yards such as BAE Systems’ facility in Barrow.