The US-built Lockheed Martin Lightning II fleet was officially cleared on Monday, according to Defence Minister Linda Reynolds.

"For the last two years, Defence has rigorously tested the F-35A fleet to assess aircraft and system performance, and declare this important milestone," she said.

Senator Reynolds said reaching the milestone wasn't easy in a year disrupted by the coronavirus pandemic.

"Travel restrictions made it difficult to ferry our aircraft to Australia," she noted.

The milestone comes two years after the first F-35A was acceptd into Australian service in 2018.

The supersonic stealth fighters carry advanced electro-optical and infrared sensors and radar and can fire a "wide range" of air-to-surface and air-to-air weapons.

Australia has committed to 72 of the jets, which will be distributed to operational squadrons at RAAF Base Williamtown and RAAF Base Tindal, as well as a training squadron at Williamtown.

All are exected to be fully operational by 2023.

Monday's announcement means the Australian Defence Force now has an F-35A squadron ready to conduct "technologically advanced strike and air combat roles".

The fifth-generation F-35As will work alongside Australia's F/A-18F Super Hornet and EA-18G Growler air assets.

Australian Associated Press