The increased cost of the $16 billion acquisition will be due to the third production delay to the next-generation jet in as many years and caused by the $487 billion ($473 billion) in cuts to US defence spending over 10 years.

Mr Fitzgibbon, who was minister for defence from 2007 to 2009, has been vocal about the cost of the next-generation Lockheed Martin jet, touted as the future of air warfare. ''F35 unit costs will rise due to US Defence cuts,'' he wrote on Twitter yesterday. ''Entirely predictable and one of a number of reasons I declined opposition pressure to sign.''

While minister he led a charge to recommend the government delay a final decision to sign up to the US-built plane so as to lobby for a lower price.

''I am determined not to sign on the dotted line of the JSF before I have got, as close as you can, a guarantee on cap, price and schedule,'' he said in 2008.

But yesterday the acting Minister for Defence, Warren Snowdon, said via email that a US production delay ''should not affect Australian JSF aircraft production''. ''While the US deficit reduction measures may result in a slower ramp up in JSF production over the next few years, at least some of this spare production capacity can be expected to be absorbed by new foreign customers, such as Japan,'' Mr Snowdon said.

Australia has set aside as much as $16 billion to buy 100 of the fighters but that purchase is under a cloud after the Minister for Defence, Stephen Smith, warned more cuts to the program could force Australia to re-evaluate its position.

Design faults with the JSF have meant the projected cost per aircraft has risen from $US50 million in 2002 to more than $US120 million last year. The latest news will place more pressure on the government to scale back the number of jets it buys.

The government has agreed to purchase at least 14 and as many as 100 of the next-generation fighters but remains concerned about the continuing production problems.

The first batch is due to be delivered by 2014, at a cost of $3.2 billion. Some speculate that Australia may finally buy fewer than 60 of the jets.

The US defence cuts come only weeks after the leaking of a report into the beleaguered jet by a Pentagon panel of experts calling for a production slowdown to fix a suite of design faults, which itself could see a cost blowout.

Thirteen issues were identified during the review, which was published in November and leaked to a US website four weeks later, including five described as being of ''major consequence''.

Those five include problems with the pilot's helmet display and a design flaw in the power package, which grounded the fleet for two weeks in August.

One of the five faults of concern was referred to in the report as ''classified'', and there has been speculation it may relate to the JSF's stealth skin.