Bangkok: Philippines President Rodrigo Duterte has declared it is "time to say goodbye" to the United States as he steered his country towards Beijing's sphere of influence during a red-carpet state visit to China.

"No more American influence. No more American exercises. It's time to say goodbye, my friend. Your stay in my country was for your own benefit," Mr Duterte said, referring to his country's long alliance with the US, its former colonial power.

"I will not go to America anymore. I will just be insulted there," he added, before once again referring to US President Barack Obama as the "son of a whore".

The comments aimed at the US's strongest ally in Asia over decades will further alarm policy-makers in the US and its allies in Asia and the Pacific, including Australia.