Japanese Foreign Minister Fumio Kishida has delivered a blunt message to Canberra that only its bid to build Australia's new $50 billion submarine fleet can provide the crucial "strategic" element. 
In a meeting with Foreign Minister Julie Bishop in Tokyo, Mr Kishida appeared to play up to perceptions the Japanese bid was favoured by the United States, amid reports Washington was uneasy about handing over sensitive weapons technology to the French consortium.
Mr Kishida said the Japanese bid was "strategically significant", according to a briefing given to local reporters after the meeting. Ms Bishop confirmed "Japan has emphasised the strategic importance of their bid".
"Our focus is very much on capability [of the submarines] but other factors will be taken into account," she said on Monday night.
"In the case of Japan they speak about it [the bid] in a strategic context."
Japan is touting its bid as a way to build military ties between Canberra and Tokyo, a tie up favoured by the US.
But such a tie-up is likely to cause unease in Beijing, as it would be seen as an effort to counterbalance China's growing regional power. The Japanese and French consortiums are believed to be the front-runners to win what is the world's largest defence contract, with the German bid lagging due to technical concerns.
The Financial Times reported earlier this month that Washington was concerned about technology "leakage" of advanced weapons systems from the French consortium.
A decision on the 40-year construction and maintenance contract is expected mid-year after the release of Australia's new Defence white paper.
The white paper is expected to outline Australia's plans to build 12 new submarines to replace the ageing and much-maligned Collins-Class submarines.
The Japanese were the early favourites to win the bid, but the race has significantly tightened since the demise of Tony Abbott as Prime Minister.
He described Japan as Australia's "best friend in Asia" and led the upgrading of military ties, which Tokyo has described as a "quasi-alliance".
Prime Minister Malcolm Turnbull has taken a more neutral tone towards competing bidders and emphasised the need for technology transfer and alignment with his innovation agenda.
Japan's lack of experience in managing overseas defence contracts is seen as problem for its bid, as was its failure to include detailed budget plans in its initial proposal.
Ms Bishop will go to Beijing on Tuesday after wrapping up two days of meetings in Tokyo, which will include a call on Prime Minister Shinzo Abe.
In China she will meet with Foreign Minister Wang Yi and has pledged to seek an explanation from Beijing over its actions in the disputed South China Sea.
China has been rapidly reclaiming land around low lying atolls in the South China Sea and has constructed military-grade runways and other defence infrastructure.
China has said this will be used for humanitarian purposes such as search and rescue operations.
Ms Bishop said she took at face value President Xi Jinping's insistence that China did not intend to militarise the islands, which are subject to a series of interlocking territorial claims from China's south-east Asian neighbours.