Major countries should take the lead in respecting the authority of international law and fulfilling their obligations under the law, the Foreign Ministry said on Wednesday after United States President Donald Trump dismissed international law.

"I don't need international law. I'm not looking to hurt people," Trump said in an interview with The New York Times last week.

Trump said the only constraint to his power as president of the US is "my own morality, my own mind".

Mao Ning, the ministry's spokeswoman, said that international law — based on the purposes and principles of the United Nations Charter — is a cornerstone of the existing international order, as well as an important basis for addressing international disputes.

Upholding international law is key to defending international fairness and justice and preventing a return to the law of the jungle, she said.