Japanese and U.S. trade chiefs have agreed that both sides need to make further efforts for the conclusion of the Trans-Pacific Partnership free trade pact at an early date.

Akira Amari, minister in charge of the TPP negotiations, suggested that he and U.S. counterpart Michael Froman discussed during a teleconference Monday how to deal with the tariffs Japan is seeking to retain on five sensitive farm product categories, but he declined to elaborate.

"It is very important to thrash out (unresolved issues) at the chief negotiators' level" before the next ministerial meeting planned for February, Amari said after the teleconference.