Japan's effort to charm Australian politicians and the public over its bid for a 50 billion Australian dollars (¥426 billion) submarine project appeared to stumble Wednesday, with officials from Tokyo resisting pressure to commit to building the vessels in Australia.

Japanese defense officials and executives from Mitsubishi Heavy Industries and Kawasaki Heavy Industries made their first major pitch to build 12 stealth submarines for Australia's navy during public briefings for defense contractors and the media in Adelaide, a ship-building hub.

Once seen as the front-runner to win the contract, the Japanese bid has since come under scrutiny because of Tokyo's unwillingness to commit to building any submarines in Australia, where manufacturing jobs are a hot-button political issue.