Vice Trade Minister Osamu Watanabe expressed concern Thursday that trade friction may grow between Tokyo and Washington this year, with U.S. economic growth likely to slow after years of booming.

Expecting that the U.S. economy "will surely show a tendency to decelerate" this year, Watanabe said Congress is likely to increase its complaints against the blossoming bilateral trade imbalance in areas such as steel and auto parts.

"As (Japan and the U.S. are) the world's top two economies, it is inevitable for us to face such trade friction. The question is how we should deal with the matter in order to prevent it becoming an unnecessary political problem," Watanabe told a regular press conference.

Watanabe acknowledged that behind the soaring trade deficit in the U.S. is the nation's sound economy and Japan's shrinking one, and reiterated the need for Tokyo to do its utmost to boost domestic demand.

However, he flatly denied the possibility of Japan placing self-imposed restraints on exports to avert trade rows, as such a move runs counter to the spirit of the World Trade Organization.