American diplomat Kurt Campbell suggests Australia's AUKUS nuclear submarines could be to defend Taiwan against China

A top US diplomat has suggested his country would expect Australia's planned nuclear-powered submarines to be used if it went to a war with China over Taiwan.

Deputy Secretary of State Kurt Campbell spoke about the AUKUS submarines during an appearance last week at the Centre for a New American Security in Washington.

Dr Campbell said the US was facing 'a number of potential areas of conflict' in the Indo-Pacific which would require the cooperation of its AUKUS allies and other regional partners. 

The federal government has committed to building a fleet of British-designed nuclear-powered submarines in Adelaide under the trilateral AUKUS security program. 

Prime Minister Anthony Albanese said in March last year the plan, which included buying at least three American submarines, would cost taxpayers $268billion to $368billion over the next 30 years.

Mr Albanese, US President Joe Biden and British Prime Minister Rishi Sunak have all talked up the number of jobs that will be created in their countries under the alliance. 

But in his comments last week Dr Campbell seemed to make it clear the US saw AUKUS as playing a part in any conflict in the Taiwan Strait with China. 

'I think those practical circumstances in which AUKUS has the potential to have submarines from a number of countries operating in close coordination that could deliver conventional ordinance from long distances,' Dr Campbell said. 

'Those have enormous implications in a variety of scenarios, including in cross-strait circumstances...

'And so I think I would argue that working closely with other nations, not just diplomatically, but in defense avenues, has the consequence of strengthening peace and stability more generally.' 

Dr Campbell said Mr Albanese, Mr Biden and Mr Sunak all needed to 'underscore constantly' their support for AUKUS.

'I think all countries, each of these countries need to underscore that this is not a jobs program, it is not a technology development program,' he said in Washington. 

'Those are corollary advantages. 

'This is a security partnership that is profoundly constitutional and has the potential to not only create fundamentally new realities... in the water in Asia, but also change the nature of the way each of our three countries operate together.'

Mr Albanese has consistently said Australia would main sovereign control over the use of the submarines if its interests did not align with those of the US or UK in wartime.

Dr Campbell reportedly told European Union officials two years ago that AUKUS was about 'getting Australia off the fence - we have them locked in now for the next 40 years'. 

In June last year, Dr Campbell told the Center for Strategic International Studies how Australia would be expected to deploy US-built submarines during a discussion on the strategic implications of AUKUS. 

'I would also just remember that when submarines are provided from the United States to Australia, it's not like they're lost,' Dr Campbell said. 

'They will just be deployed by the closest possible allied force.'

A prominent Australian defence expert has previously said the AUKUS deal could lead the nation into being forced to follow the US into a war against China.

The Australian National University's Hugh White, a former deputy secretary of the Defence Department, slammed AUKUS in March last year just days after details of the program were announced.

'This is a very serious transformation of the nature of our alliance with the United States,' Professor White told the ANU's politics podcast Democracy Sausage.

'The US don't really care about our submarine capability - they care deeply about tying Australia into their containment strategy against China.'

Australia plans to purchase up to five US-made Virginia-class nuclear submarines as a stopgap measure before eight SSN-AUKUS sub are built in Adelaide, with the first to be completed by 2042.

Professor White could not see why the US would sell its own submarines - of which they have fewer than they need - unless it was sure Australia's submarines would be available to it in the event of a major conflict in Asia.

He said a war between America and China over Taiwan would be 'World War III' and have a 'very good chance' of being a nuclear conflict.

'Australia's experience of war (is) shaped by the fact that we've tended to be on the winning side, but there is no reason to expect America to win in a war with China over Taiwan,' he warned.

He suggested there was also a high chance the AUKUS deal could fall over under a future American administration and a worsening strategic environment.

Professor White said there were cheaper, quicker, less risky and less demanding ways for Australia to get the submarines it needed, labelling the AUKUS plan a waste of money that 'doesn't make sense'.

'There's going to be no actual net increase in the number of submarines available until well into the 2040s, even if it goes to plan - which it probably won't,' he said.