The Federal Government is scrapping or delaying major Defence projects, including the Joint Strike Fighter, in a drive to save billions of dollars over the budget's forward estimates

Prime Minister Julia Gillard announced the rethink today as she revealed that the next Defence Force White Paper, originally due in 2014, was being brought forward by a year.

Among the announcements today:

The delivery of the RAAF's first 12 Joint Strike Fighters will be delayed by two years

The delivery of the RAAF's first 12 Joint Strike Fighters will be delayed by two years The Government reaffirmed its commitment to build 12 new submarines in Adelaide

The Government reaffirmed its commitment to build 12 new submarines in Adelaide More than $200m will be spent on a study to decide if the subs should be bought from other countries or designed from scratch

More than $200m will be spent on a study to decide if the subs should be bought from other countries or designed from scratch Plans to equip the Army with new self-propelled artillery are being scrapped, saving $250m

Plans to equip the Army with new self-propelled artillery are being scrapped, saving $250m The new ADF Posture Review recommends stepping up the Defence presence in north-west Australia.

Ms Gillard said it was time to "re-calibrate" Australia's defence strategy because of the Afghan withdrawal plans and what she said was "the changing global distribution of power".

But she promised that the cuts would not have an effect on troops on active service.

"I want to be very clear today that this contribution has been carefully designed to protect our servicemen and women and our Defence operations, and to minimise the impact on core project capabilities," she said.

"In particular, the budget will protect our men and women on the front line. They will get all of the kit and support that they need. There will be no impact on any of our overseas operations."

Delivery of the first 12 F-35 Joint Strike Fighters will be delayed by two years. ( www.is.northropgrumman.com )

Defence Minister Stephen Smith said he spoke with his US counterpart Leon Panetta this morning, assuring him the cuts would not affect the US-Australia alliance.

"We remain committed to the Joint Strike Fighter project, but we will see the delivery of our first 12 Joint Strike Fighters two years after the previous estimates at a net benefit to the budget of $1.6 billion, putting us on the same timetable effectively as the United States," Mr Smith said.

And he hailed plans to spend $200 million on a study for a new submarine fleet to replace the troubled Collins class vessels.

"This will be the largest Defence capability project the Commonwealth has embarked upon," he said.

"The big mistake of Collins, in addition to some design deficiencies, was we did not take in to account at the time ... what the burden of maintenance and sustainment would be.

"So we're not making that mistake with the future submarine."

Opposition leader Tony Abbott says the decision to bring the white paper forward is an admission of failure by the Government.

"This is a Government which has been sitting on its hands for the last three years when it comes to important decisions about our defence capabilities," he said.

"It's only three years since the last White Paper. This is a confession of failure."