Aust can't build subs: Japanese skipper

A former Japanese submarine commander claims Australia doesn't have enough skilled workers to build the Soryu class subs.

Japan is best placed to build the high-tech vessels, which are being considered as replacements for Australia's ageing Collins fleet, Captain Hisayuki Tamura from the Japanese Ministry of Defence has told the ABC.

"They don't have enough skilled workers to fashion the high-tension steel; it's even hard to do in Japan," he said of Adelaide shipbuilder ASC.

South Australian independent senator Nick Xenophon said the comments were "very disturbing".

"My information is that both the Germans and the French who are bidding to build submarines here in Australia say that is nonsense," he told reporters in Canberra.

"This is bad news, a bad sign, if this is typical of a broader attitude in the Japanese defence establishment and within the Japanese government."