Australia may need a ‘Plan B’ if the high-tech but low-functioning F-35A aircraft project is delayed.

The Senate committee investigating the multi-billion-dollar Joint Strike Fighter scheme has heard concerns about the aircraft's manoeuvrability, stealth capabilities, escape system and other features.

The committee says the F-35 variants are the only aircraft suitable for Australia's strategic needs.

However, the Senators’ report says they hold a ‘healthy scepticism’ of the claims about the aircraft, its costs and delivery time from US proponents.

The committee has called for the Department of Defence to come up with a ‘hedging strategy’ in case delays continue.

The Australian Strategic Policy Institute has previously advised that the “most sensible hedge” would be more F/A-18F Super Hornets – a move the committee has considered.

The committee said any backup strategy should be capable of implementation by 2019.