The government may have decided which submarine Australia will buy but if so, it hasn't told the bidders.
That follows one media report, in the Wall Street Journal, suggesting German shipbuilder TKMS was favourite and another in The Australian newspaper saying French firm DCNS was frontrunner.
Chairman of TKMS Australia Dr John White said he hadn't been told anything.
"The defence committee and the national security committee are as tight as a deep diving submarine," he told AAP.
Similarly, a spokeswoman for DCNS said they had not been told nothing.
A spokesman for Prime Minister Malcolm Turnbull declined to comment.
The Wall Street Journal report said the final decision would be a choice between the German and French bids, with TKMS a strong contender because of its extensive experience building subs in Germany and in customer shipyards.
Japan's was viewed as having considerable risk given the country's lack of experience exporting complex defence equipment.
The Japanese offer of the Soryu class submarine was seen to be favoured by Tony Abbott when he was prime minister.
The Australian said France's bid to build a submarine based on its Barracuda nuclear attack sub was shaping up as frontrunner while the Japanese bid was considered the weakest of the three.
The final decision is expected to be announced next week in Adelaide where the new submarines will be built.
The Japanese embassy in Canberra has been approached for comment.