Australian Defence Minister Stephen Smith was Friday forced to defend deep spending cuts after the announcement was called the worst day for national security since the Vietnam war ended in 1975.
Smith on Thursday announced a delay in the order of 12 F-35 Joint Strike Fighter jets by two years to save money in an aggressive drive to return the national budget to surplus.
Canberra will also scrap plans to equip the army with new self-propelled artillery.
The fighter jet move will provide a Aus$1.6 billion (US$1.64 billion) boost to the bottom line, with reports Friday saying it was just part of between Aus$4 to $5 billion of cuts that will be announced in the budget on Tuesday.
Defence analysts quoted in the Fairfax press said it was potentially the largest slashing of spending since the end of the Vietnam conflict, an angle driven home by News Limited, which said the government was in "la-la land".
"This is the worst day for Australia's national security since the fall of Saigon in 1975," The Australian's foreign editor said in an opinion piece.
"It is the day the Gillard government declared it has no intention of providing a significant defence capability for Australia."
Smith called the criticism "nonsense".
"I just think it's a nonsense statement," he told ABC radio, and said the cuts were "manageable".
"We believe that we have ring-fenced the core capability that we need and the core contributions and obligations that we have at the moment so far as our field operations are concerned," he said.
Australia is a key ally of the United States and the two have recently reinforced their defence cooperation in a significant geo-strategic shift by Washington that has irked Beijing.
Smith said he spoke to his US counterpart Leon Panetta Thursday morning and assured him the cuts would not affect the US-Australia alliance.
Mining-powered Australia was the only advanced economy to weather the global downturn without entering recession, and returning the budget into the black is seen as a key test of the struggling Labor government's economic management.
In announcing the decisions, Prime Minister Julia Gillard guaranteed that overseas defence operations would not be impacted by the spending cuts and there would be no reduction in military numbers.