"If a relationship of trust is not rebuilt, it will be difficult to have a dialogue on trade management and policy," Jun Iwamatsu, director of trade control policy at Japan's Ministry of Economy, Trade and Industry told a news conference.

Export curbs imposed by Japan this month have had absolutely no impact on global supply chains, Iwamatsu said.

A row over compensation for Korean forced labourers has spilled over into trade between the two U.S. allies in high-tech materials used to make memory chips and screens.

Relations been the neighbours have been difficult for decades because of South Korean resentment of Japan's 1910-1945 occupation of the Korean peninsula.

(Reporting by Yoshifumi Takemoto; Writing by William Mallard; Editing by Robert Birsel)