TOKYO: Philippine President Rodrigo Duterte sought to assure Japan on Wednesday that his high-profile visit to rival China last week was only about economics, but had more harsh words for long-time ally Washington, saying he might abrogate defence treaties.

The volatile Philippine leader's visit to Japan comes amid jitters about his foreign policy goals after weeks of verbal attacks on ally the United States and overtures towards China.

Duterte last week announced in China his "separation" from the United States, but then insisted ties were not being severed and that he was merely pursuing an independent foreign policy.

His perplexing comments pose a headache for Japanese Prime Minister Shinzo Abe, who has tightened ties with Washington while building closer security relations with Manila and other Southeast Asian countries as a counter-weight to a rising China.

"You know I went to China for a visit. And I would like to assure you that all there was, was economics. We did not talk about arms. We avoided talking about alliances...," he told an audience of Japanese businessmen.

"We did not talk about arms. We did not talk about stationing of troops. We avoided talking about alliances."

Calling Japan a "long-standing friend and ally", he also called for Japanese investment in infrastructure, agriculture and other sectors.

Duterte said he did not pick quarrels with his neighbours, but had tough words for Washington, threatening once again to revise or cancel Manila's defence pacts with the United States and insisting the Philippines was not "a dog on a leash".

"I have declared that I will pursue an independent foreign policy. I want, maybe in the next two years, my country free of the presence of foreign military troops. I want them out," he said. "And if I have to revise or abrogate agreements, executive agreements, this shall be the last manoeuvre, war games between the United States and the Philippines military."

Duterte has threatened to abrogate defence agreements with the United States several times over the past two months, but has yet to take any concrete action beyond cancelling some minor navy patrol exercises.

Duterte is set to meet Abe for bilateral talks later on Wednesday.

Duterte's apparent cosying up to Beijing has both Tokyo and Washington worried that the commitment under former Philippine President Benigno Aquino to stand up to China in the hotly disputed South China Sea is under threat.

Aquino angered China by lodging a case with an arbitration court in the Hague challenging the legitimacy of Beijing's maritime claims in the resource-rich sea. A ruling earlier this year emphatically favoured Manila but was rejected by China, which has warned Washington and Tokyo to stay out of the feud.

Duterte on Wednesday, however, sought to reassure Japan that his friendship was firm despite his row with Washington.

"We would like to make the guarantee that we will also be a partner in the player of maritime safety, maritime security in the China sea and that we would like to avoid at all costs violence because ... we have to resolve it peacefully and in accordance with international law," he told Japan's main business lobby in later remarks.

"Japan is an old and reliable friend of the Philippines. This is a special friendship we hope to keep and continue."