Australia's defence chief is defending the acquisition of second-hand submarines, despite concern taxpayer money is being spent on lesser equipment than first promised.
Chief of the Defence Force David Johnston told a senate estimates committee three used Virginia-class submarines, to be acquired through the AUKUS pact, would be "highly capable".
The $368 billion plan originally had Australia receiving three nuclear submarines from the US - two used and one new Virginia-Class vessels - before building its own in Adelaide.
