Prime Minister Tony Abbott tries out the cockpit of the F-35 fighter plane in Canberra, Wednesday, April 23, 2014.

Prime Minister Tony Abbott tries out the cockpit of the F-35 fighter plane in Canberra, Wednesday, April 23, 2014. ALAN PORRITT

DESPITE fears of major cuts to welfare to come in the Abbott Government's first budget, the Coalition has found $12 billion to buy 58 new fighter aircraft for the Defence Force.

The much-delayed purchase of the F-35 Joint Strike Fighter planes as well as Super Hornets and Growler electronic warfare aircraft will appear in the May budget.

It will be the single largest spend on Defence assets in Australian history, the government has said, and follows Prime Minister Tony Abbott's election commitments to increase the overall defence budget.

Originally proposed by then-Prime Minister John Howard, cost over-runs and delays hit the multi-national JSF project.

Despite the need for budget savings dominating headlines for weeks, Mr Abbott on Tuesday argued the project was needed to "ensure Australia maintains a regional air combat edge".

Mr Abbott said the massive purchase would bring "significant economic benefits to Australia, including in regional areas", likely through manufacturers in South Australia and Victoria.

The total cost of the project includes $1.6 billion in new infrastructure at RAAF Base Williamtown in New South Wales and RAAF Base Tindal in the Northern Territory.

Overall, the project will see the first new F-35 aircraft arrive in Australia in 2018, to enter service by 2020, with the remaining 58 to enter service in following years.

The 58 new jets approved by the Abbott Government will be in addition to the 14 approved by the previous government in 2009.