Australia has been warned its first French-designed Attack-class submarine is likely to be inferior to those operated by neighbouring countries, and may even prove "obsolete" before it's due into service in the 2030s.

Key points: Australia's objective to produce a "regionally superior" submarine is "now under challenge"

Australia's objective to produce a "regionally superior" submarine is "now under challenge" An analyst says other countries are building boats with lithium-ion battery propulsion, which allows higher speeds and longer time underwater

An analyst says other countries are building boats with lithium-ion battery propulsion, which allows higher speeds and longer time underwater Defence Minister Linda Reynolds joins French President Emmanuel Macron for first official inspection of new Suffren-class subs

A new report by veteran military analyst Derek Woolner, and fellow researcher David Glynne Jones, is urging the Defence Department to urgently embrace cutting-edge lithium-ion battery propulsion for its future submarines.

Their report concludes that Australia's objective for the $50 billion Attack-class program to produce a "regionally superior" submarine is "now under challenge".

"By the time HMAS Attack [the first of the new submarines] hits the water in the early 2030s, it's going to be obsolete," Mr Woolner has told the ABC.

The former government advisor said HMAS Attack would be built with a heavy metal main battery, as part of a process already initiated under a contract signed by France's Naval Group company and MTU Friedrichshafen for diesel generator sets.

"A number of countries in the region are already proceeding to build boats around lithium-ion batteries that promise something like five to six times the submerged stealthy performance and a great deal more high-speed performance than you can get from a lead-acid battery submarine".

Analyst Derek Woolner has urged Australia to switch to lithium-ion battery propulsion, away from heavy metal batteries. ( Supplied: DCNS )

In 2016, former prime minister Malcolm Turnbull announced Naval Group (then known as DCNS) had beaten rival bids from Germany and Japan to build 12 new submarines for the Royal Australian Navy over the next three decades.

Mr Woolner, who completed some early contractual work on Australia's Future Submarine program, believes the Defence Department must now act quickly on battery technology.

"I would like to see the Defence Force invest in this at a very early stage, to overcome the obsolescence problem that's going to face the Future Submarine before it even gets into naval service."

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

A Defence spokesperson said lithium-ion battery technology had yet to be proven.

"The Attack class will be a new design optimised as a conventionally-powered submarine that meets our unique capability requirements," Defence said in a statement.

"Lithium-ion battery is a new technology and is yet to be fully proven at sea.

"During the design of the Attack class submarine, Defence continues to make informed decisions on technology and the risks going forward.

"Over the acquisition program for 12 submarines, Defence has the opportunity to introduce new technologies to the future submarine fleet as they demonstrate their ability to meet our needs."

Macron praises Australian partnership as France unveils new nuclear sub

Warnings about Australia's conventionally powered future submarines have emerged as France celebrates the public unveiling of the first of its six nuclear-powered Suffren-class submarines.

French President Emmanuel Macron inspects the nuclear-powered Suffren submarine in Cherbourg. ( AP: Ludovic Marin )

Australia's yet-to-be designed Attack class submarines will be roughly based on the Suffren-class boats.

On Friday, Defence Minister Linda Reynolds joined French President Emmanuel Macron at Naval Group's Cherbourg shipyards for the first official inspection.

"Our partnership is an industrial one but it is also above all a partnership between governments, a partnership between nations," Mr Macron told his Australian guest.

Naval Group chief executive Herve Guillou also praised the decision to choose France to help build Australia's fleet of 12 new submarines.

"Our common future, Minister, for the next 50 years [is] to deliver sovereignty and regional superiority to your country," Mr Guillou said at the unveiling ceremony.

"Your presence today highlights the depth of the strategic partnership and links that bind now our two countries."