The rare public comments by Mr Shearer provide an insight into the sentiments influencing Mr Abbott during his reign as prime minister, before he was dethroned by Malcolm Turnbull.

Some US defence hawks were originally on alert for Prime Minister Turnbull to pivot closer to China, potentially at the expense of the US alliance, but he has maintained a similar defence posture to Mr Abbott.

Mr Shearer, a pro-US defence hawk, made the frank remarks at the launch of his report, Australia-Japan-US Maritime Cooperation, at the Center for Strategic and International Studies where he is a visiting fellow.

The findings clash with the more dovish views on China expressed by foreign affairs strategist Hugh White, who has suggested Australia should loosen its defence ties with America to make way for China's economic rise.

Andrew Shearer says China is 'continuing to roll out its long-term strategy for establishing military control over the South China Sea.

Mr Shearer recommends Australia, Japan and the US build on existing interoperability in areas such as intelligence, undersea warfare, reconnaissance, training and weapon systems. More cooperation could help overcome US government defence spending cuts.

On the Turnbull government's contentious $50 billion tender to build 12 new submarines, he supports Japan being awarded the contract over German and French competitors.

"If the capability of the Soryu can be modified to the minimum extent possible to meet Australia's requirements ... and if the Japanese proposal is solid on cost and schedule ... then I think the strategic logic in going with the Japanese is compelling," Mr Shearer said.


Privately, the US Pentagon is understood to favour Japan winning the bid, for strategic and interoperability reasons.

However, the official public US position is that it does not take sides in Canberra's sovereign decision. Seated beside Mr Shearer, US assistant secretary of defence, Robert Scher, said "we will work with whatever submarine the Australians choose".

The CSIS report comes in wake of Republican presidential frontrunner Donald Trump threatening to pull back US forces from Asia, opposing the Trans-Pacific Partnership trade deal and suggesting that Japan and South Korea acquire nuclear weapons for protection.

Foreign Affairs Minister Julie Bishop responded last week that Australia would never support nuclear proliferation.

Mr Scher said America had always overcome isolationist streaks in the past and would continue to engage internationally, no matter who wins the November election.

"It is in our interests to have an international approach," he said.

Mr Scher said new trilateral cooperation between Australia, Japan and the US would be a "key piece" of promoting a rules-based order and economic prosperity in Asia.

Beyond the "obvious first choice" partners, India, South Korea and Singapore also had important capabilities, he said.


Mr Shearer, who previously worked as prime minister John Howard's national security adviser, said cuts to the US defence budget meant like-minded allies had to collaborate more to counteract rising threats.

China is ramping up military spending, though the US still spends more on its military than the next top eight nations combined, President Barack Obama said in his state of the union speech in January.

Mr Scher pushed back against the idea that US military influence in the region was heading for an inevitable decline.

"I wouldn't trade our navy for China's navy," he said.

The Turnbull government has committed to restoring defence spending to 2 per cent of GDP. Japan is also increasing military spending, but other allies around the world are cutting defence outlays as their budgets come under pressure from weak economic growth.