Prime Minister Yoshihiko Noda on Thursday postponed his widely expected announcement that Japan will join the U.S. and other countries in negotiations over the Trans-Pacific Partnership, saying he wanted to sleep on the issue for a day before making his final decision.

At a meeting between the government and Democratic Party of Japan executives in the afternoon, Noda said he "wanted to gravely consider (the opinions of DPJ lawmakers who oppose joining the free-trade talks), and thoroughly consider what everyone had discussed," Chief Cabinet Secretary Osamu Fujimura said.

Noda has been careful not to create any waves since becoming prime minister in September, but making a political decision to join the TPP talks is likely to trigger harsh anger from opponents of the free-trade framework in the DPJ and could split the party.