Upgrades to Australia's ageing Collins-class submarines will be reduced in scope as the federal government tries to get another decade out of the boats before the arrival of a nuclear-powered fleet.
The Albanese government says it will be changing its sustainment approach to the submarines, meaning not all six boats will have key systems such as engines and motors replaced.
Addressing the Lowy Institute on Tuesday, Defence Minister Richard Marles said the $11 billion program would be "conditions-based".
"This will see a pivot in our approach that reduces risk, upgrades capability and maximises availability for the navy," he said.
"We will prioritise sustainment and accelerate upgrades for the fleet's youngest submarines.
"The program will reduce engineering risk by sustaining existing systems where appropriate while continuing to upgrade critical capabilities, including weapons and combat systems."
