Subs plan will cost govt seats: Xenophon

Independent senator Nick Xenophon has warned the coalition it stands to lose both votes and seats for backing away from an undertaking to build 12 new submarines in Adelaide.

Senator Xenophon said the government process had shown cavalier disregard for the economic benefits of building the new submarines and also warships in Australia.

"Make no mistake, the government's attempts at backing away from its promise to build 12 future submarines in South Australia ... will cost them votes and seats in my home state," he told the National Press Club on Wednesday.