Planned upgrades for Australia’s Collins-class submarines to extend their service life will be dramatically wound back, with not all six of the ageing boats to receive new motors and engines before they’re eventually replaced by a nuclear-powered fleet.

The Albanese government will instead pursue an “enhanced sustainment” approach where HMAS Farncomb, one of the oldest boats and most heavily used, will begin a “Life of Type Extension” within days, before other submarines are individually assessed.

“Informed by independent expert advice, detailed planning and industry engagement Defence will undertake a conditions-based sustainment approach across the life of type extension program,” the government said in a statement.

“This will see Defence and ASC retain and restore base components, while continuing to upgrade critical weapons and systems. This will reduce engineering and schedule risks and ensure the Collins class remains a formidable deterrent for years to come.”

Addressing the Lowy Institute, the defence minister has confirmed the LOTE program will begin at the end of the month and cost $11 billion for the entire Collins fleet, up from an estimated $6 billion allocated in 2020 under the Morrison government.

“This will see a pivot in our approach that reduces risk, upgrades capability and maximises availability for the Navy. We will prioritise sustainment and accelerate upgrades for the fleet’s youngest submarines,” Richard Marles said.

“The program will reduce engineering risk by sustaining existing systems where appropriate while continuing to upgrade critical capabilities, including weapons and combat systems.”

“It has the transition to our future fleet of conventionally-armed, nuclear-powered submarines as a key consideration,” Mr Marles told his Melbourne audience.

Under the massive AUKUS endeavour, Australia is hoping to extend the life of its Collins-class fleet, which began entering service 30 years ago, by another decade before the Navy transitions to Virginia-class nuclear boats from the United States.

Defence says a “detailed engineering assessment period” will be carried out on HMAS Farncomb to tailor its life of type extension upgrades and to “inform work required across the class”.

Previous “life-of-type extension” plans included new main motors, diesel engines, and electrical generators for each of the six Collins-class boats to keep them running until the arrival of the navy’s planned fleet of nuclear submarines in the 2030s.

The government insists safety will not be compromised and the Collins class will be supported by increased investment of up to $11 billion over the next decade, but there is no guarantee any of the boats will have all their critical systems replaced.

A classified review commissioned by the Albanese government in 2023 and written by US expert Gloria Valdez is believed to have recommended that Australia not complete upgrades on all six of its ageing Collins-class boats before they’re retired in the 2040s.

“These decisions reaffirm the Albanese Government’s commitment to keeping the Collins class a potent and highly capable strike and deterrent capability today, and for years to come,” Mr Marles said.

Shadow Defence Minister James Paterson has taken aim at the Albanese government’s announcement, accusing Mr Marles of failing to properly secure enough funding for vital military projects.

“Richard Marles has used the cover of a remarkably partisan and defensive speech to admit a major descoping of the Collins class life of type extension. As is often the case, he’s failed to provide the details transparently to the public.”

“Which aspects of upgrades previously planned are now being abandoned? And how much is the Albanese government cutting from the program?” Senator Paterson demanded to know.

“If Richard Marles put as much energy into persuading his expenditure review committee colleagues as he does attacking the previous government, maybe the ADF wouldn’t have to absorb as many cuts to capability as it has on his watch.”

Greens Senator and the party’s defence spokesperson David Shoebridge has derided the government’s revamped LOTE announcement as “$11 billion more washed down the AUKUS drain”.

“We have known for years that this ‘life-of-type’ extension that Defence is dropping $11 billion on is extremely risky. This is what happens when you have a Department of Defence that is never held to account for failures and the war parties backing them in.”