"Together with the Super Hornet and Growler electronic warfare aircraft, the F-35 aircraft will ensure Australia maintains a regional air combat edge."
Opposition leader Bill Shorten said the fighter was "an appropriate addition to [the nation's] airpower".
The JSF, one of Australia's most expensive defence purchases, uses stealth technology to avoid enemy radar and employs what its proponents say is the world's most sophisticated technology to detect and destroy targets at vast distances.
It carries air-to-air missiles and guided bombs.
The Government will also spend A$1.6 billion building new facilities at Williamtown near Newcastle, north of Sydney, and at Tindal, outside Katherine in the Northern Territory.
The cost will be partly offset by work for local industry, already involving more than 30 companies and contracts worth A$330 million.
Defence Minister David Johnston said yesterday that another A$1.5 billion worth of work could be won in the next three or four years, with a "significant slice" of more than A$7.5 billion in further contracts on the table for Australian business.
"We're talking about a highly advanced technological stealth weapon that can sense an adversary at a long long range off and provide Australia with cutting-edge capability in terms of national defence," Johnston told the ABC.
But the decision to buy the fighter comes amid continuing controversy over its suitability for the RAAF, technical problems, delays, cost overruns and doubts over the final bill. "If you think more about your military needs being the Afghanistan-style operations, the troubled waters of the South China Sea, counter-piracy, peace operations, keeping some degree of regional calm with some turbulence in the Asean region but not necessarily China, then frankly it's a debatable proposition whether the F-35 is the best bang for your buck," Michael O'Hanlon of the American Brookings Institution told the ABC.
The independent Australian defence think-tank Air Power Australia said in a scathing analysis that the JSF was not designed to perform air superiority roles, and was not well adapted for the penetrating long-range strike role filled by the RAAF's now-retired F-111 bombers.
"The JSF programme and resulting aircraft designs have, since the very first days of the programme, been burdened by fatal optimism, a total indifference to what is real, placement of form over substance," the analysis said.
Aviation experts in both Australia and the US say the JSF is outclassed in areas such as manoeuvrability by less sophisticated Chinese and Russian jets such as the Sukhoi SU-30 operated by Indonesia, and by new-generation stealth fighters including Russia's T-50 and China's Chengdu J-20 Dragon.
Costs have soared and, while the price tag has recently been trimmed, continuing delays, serious software problems and reliability issues threaten to push up the final bill.
Crucial will be the number of aircraft actually ordered. Analysts believe the US could prune its orders, and foreign partners are considering delaying or reducing their purchases. Canada and Denmark are debating whether to drop the JSF altogether.
A US congressional committee was told that because of reliability problems and the combined costs of buying, operating and supporting the JSF, the aircraft "is now deemed unaffordable".
But Johnston remains confident: "I'm very optimistic that we are seeing ... the price come down over time. If Australia decides that the costs have blown out to such an extent, we are not bound to continue."
