SYDNEY, March 19 (Reuters) - Australia "absolutely" did not promise to support the U.S. in any military conflict over Taiwan in return for a deal to acquire U.S. nuclear-powered attack submarines, Australia's Defence Minister Richard Marles said on Sunday.

Australia, the U.S. and Britain unveiled the multi-decade AUKUS project on Monday. Canberra is to buy the U.S. Virginia-class military submarines, with Britain and Australia eventually producing and operating a new submarine class, SSN-AUKUS.

Australia's centre-left Labor government says the A$368 billion ($246 billion) deal is necessary given China's military buildup in the region, which it has labelled the largest since World War Two.

Asked whether Australia had given the U.S. any commitment to help during a conflict over Taiwan in return for access to the submarines, Marles told ABC television: "Of course not, and nor was one sought".