Economic and fiscal policy minister Akira Amari admitted Friday it will be difficult to reconvene a meeting of trade ministers on the proposed Trans-Pacific Partnership free trade initiative by the end of August as had been initially planned.

Prime Minister Shinzo Abe, meanwhile, expressed confidence the countries negotiating the 12-country Pacific Rim framework can reach a broad agreement the next time the ministers meet, telling the Diet an accord will be in Japan's national interest.

"We cannot hold the next ministerial meeting unless we have certainty about reaching an agreement," Amari, who is in charge of the TPP talks for Japan, said at a press conference. "So I think (setting a date) in August would be quite difficult."