Australia's $80 billion Future Submarine Program is "dangerously off track" according to a new report that urges the Government to ditch the controversial project and consider a nuclear option.

Key points: The report indicates there are fears the current project is at a high risk of failing

The report indicates there are fears the current project is at a high risk of failing The Defence Minister denies those fears and maintains the project remains on track

The Defence Minister denies those fears and maintains the project remains on track Under a proposed "Plan B" scenario, the company that designed the Collins class submarines would prepare an updated design

Businessman Gary Johnston, who commissioned and funded the study, fears the current plan to build 12 attack class submarines designed by French company Naval Group is at "high risk" of failing.

His report, prepared by Insight Economics, suggests Australia should instead immediately begin work on a "Plan B" — an evolved version of the current Collins class fleet — before eventually acquiring nuclear-powered boats.

Earlier this year, a report from the auditor-general confirmed the Future Submarine Program was running nine months late and Defence was unable to show whether the $396 million spent so far had been "fully effective".

"The Government's own advisory body, including three American admirals, even recommended the Government should consider walking away from the project," Mr Johnston said.

Under the proposed "Plan B", Swedish company Saab Kockums, which designed the navy's Collins class submarines, would be asked to prepare an updated design for the future submarine fleet.

Australia's new fleet of submarines could already be facing an obsolescence problem over its battery power. ( Supplied: DCNS )

In 2022-23, both Naval Group and Saab will present their competing preliminary design studies for building the first batch of three submarines in Adelaide — based on a fixed price, capability, delivery and local content.

Mr Johnston, along with former naval officers in the Submarines for Australia organisation, argue that over the long term the Government should begin preparing to acquire nuclear submarines.

With Beijing's growing military assertiveness in the South China Sea, Mr Johnston said the most disturbing finding in the report was that by the 2030s the effectiveness and survivability of Australia's submarines in a high-intensity theatre would be threatened.

"If the Government wants to continue deploying submarines to this theatre alongside the US Navy, the nation's duty of care to the dedicated men and women of the ADF means we will need to begin the long and difficult process of acquiring nuclear-powered submarines," Mr Johnston said.

"With our very small nuclear industry, that will not be easy — but we can make a start."

Government rejects report, issues warning

The Submarines for Australia report will be formally launched by ANU Emeritus Professor Hugh White at the National Press Club today, but it is already drawing fire from the Morrison Government.

"I totally reject the premise that this project is 'dangerously off track', as stated in the new Submarines for Australia report", Defence Minister Linda Reynolds said.

"The delivery of the attack class submarine remains on track, with construction set to commence in 2023."

Senator Reynolds said the technical feasibility of delivering an evolved Collins class submarine was reviewed in 2013-14, but a review found it would be equivalent to a whole new design, involving similar costs and risks, without a commensurate gain in capability.

"This assessment by Submarines for Australia will only increase cost, delay the delivery, and put at risk our submarine capability."

The Defence Minister also flatly rejected any suggestion of a nuclear-powered submarine in the future.

"As has been the policy of successive Australian Governments, a nuclear-powered submarine is not being considered as an option for the attack class submarine," Senator Reynolds said.