Bangkok: Philippine President Rodrigo Duterte says he has ordered police to kill his eldest son if they can prove he is involved in smuggling or drug trafficking.

"My orders are to kill you if you are caught, and I will protect the police who kill you," Mr Duterte said he told his 42-year-old son Paolo Duterte, the vice mayor of the family's southern home city of Davao.

Paolo, who is known as Pulong, was accused of being a member of a triad via a Chinese transnational organised crime syndicate during a hearing in the Philippine Senate on September 7.

He denied the allegations, saying they were "baseless" and "rumours".