Japan's Prime Minister Kishida Fumio has arrived in the Cambodian capital of Phnom Penh, where he will attend a summit of the Association of Southeast Asian Nations.

It's the start of a busy week for the Japanese leader, who will be exercising his diplomacy through a series of key regional summits and meetings on the sidelines.

After the ASEAN meeting, Kishida will travel to the Indonesian island of Bali for a summit of the Group of 20 nations. And on Thursday, he will arrive in Bangkok for a meeting of the Asia-Pacific Economic Cooperation forum.

Kishida's eight-day tour includes trilateral talks with US President Joe Biden and South Korean President Yoon Suk-yeol.

He will also hold a one-on-one meeting with Biden. And arrangements are being made for bilateral talks with Yoon and Chinese President Xi Jinping.

Kishida plans to convey Japan's position on a number of issues such as the Russian invasion of Ukraine and its threats to use nuclear weapons. He will also reaffirm that unilateral attempts to change the status quo by force are unacceptable anywhere, including in Asia.

He will also call for cooperation to maintain and enhance freedom and the international order according to the rule of law.

In his meetings, Kishida will convey Japan's plans to support Southeast Asian nations in their efforts to recover economically from the pandemic, to de-carbonize and to enhance their food security.