The Navy says it may use Collins Class submarines for another 30 years. 

A senate committee is reviewing last month's decision to dump a $90 billion contract with France in favour of building nuclear submarines using British and American technology.

Chief of the Navy, Vice Admiral Mike Noonan, says Australia's existing csubs may need another round of upgrades before they are retired.

“I'd expect that they'd still be operating in a manner consistent with our current strategic needs and operational employment, but they will be operating with less freedom and greater risk of detection,” he said.

Labor senator Kimberley Kitching asked if this meant the Collins Class boats would still be in the water in 2040 or 2050, to which Vice Admiral Noonan said: “Yes Senator, potentially.”

All six of Australia’s Collins Class boats are in line for a life-of-type extension to give them an extra 10 years of service.

The Chief of the Navy also confirmed that borrowed US and British nuclear-propelled submarines might be needed in Australia for decades until Defence develops an understanding of the technology.

At the same hearings, Australia's nuclear regulator confirmed legislation needs to be changed and other concerns need to be addressed before nuclear-powered submarines can be operated by the Australian Defence Force (ADF).

Australian Radiation Protection and Nuclear Safety Agency chief Carl-Magnus Larsson told the committee it is not clear what precise action needs to be taken.

“I think that there are clarifications that are needed with regard, for instance, definitions, for instance nuclear powered propulsion, and there are a number of other matters that need to be looked at,” he said.