Japan's Foreign Minister Iwaya Takeshi says he will attend the inauguration ceremony of US President-elect Donald Trump on January 20.

Iwaya said in an NHK debate program on Sunday that he had accepted an invitation to the ceremony and he hopes to build a firm relationship of trust with the incoming Trump administration.

He said he is exploring an opportunity to meet with Marco Rubio, Trump's nominee for secretary of state. Iwaya added that he also hopes to meet some senior officials in the new administration to lay the groundwork for Prime Minister Ishiba Shigeru's visit to the US and his first summit with Trump.

Asked about Trump's plan to raise tariffs, Iwaya said such a move could trigger retaliatory tariffs and end up shrinking the global economy. He expressed doubt that the move will lead to a win-win situation.

He indicated that he will explain Japan's contribution to the US economy and urge the senior officials to handle the issue calmly, through close coordination with like-minded countries.

Iwaya also said if the new US administration calls on Japan to further increase its defense budget, he would seek their understanding by telling them that Japan is already making its utmost efforts.

On Monday, Iwaya is scheduled to begin a visit to South Korea, where political wrangling continues. He said he'd like to confirm with South Korean officials the importance of continued coordination between Tokyo and Seoul as well as trilateral cooperation with Washington for the region and the entire world.