MANILA • Trash-talking Philippine presidential favourite Rodrigo Duterte has warned that he is prepared to cut diplomatic ties with the US and Australia after their ambassadors criticised his joke about the jailhouse rape of a missionary.

Mr Duterte told the ambassadors to "shut their mouths" as controversy continued to rage over his comments in which he said he wanted to have been the first to rape an Australian woman who was brutalised and murdered in a 1989 prison riot.

"If I become president, go ahead and sever (diplomatic ties)," Mr Duterte, 71, said on Wednesday night, referring to the relationships with the US and Australia, two of the Philippines' closest allies.

Mr Duterte, who while campaigning has promised to kill tens of thousands of criminals, recounted at a recent rally the prison riot events as part of his tough-on-crime pitch.

"There was this Australian lay minister... they raped her, they all lined up," he told the crowd. "I was mad she was raped but she was so beautiful. I thought, the mayor should have been first."

Mr Duterte was at that time the mayor of Davao, a city in the south where he is accused of running vigilante death squads that have allegedly killed more than 1,000 people.

Australian ambassador Amanda Gorely criticised his remarks this week, saying on Twitter: "Rape and murder should never be joked about or trivialised. Violence against women and girls is unacceptable any time, anywhere".

US ambassador Philip Goldberg later agreed. "Statements by anyone, anywhere, that either degrade women or trivialise issues so serious as rape or murder are not ones that we condone," he said in an interview with CNN Philippines.

Mr Duterte has repeatedly expressed anger at what he regards as their intervention in domestic politics.

AGENCE FRANCE-PRESSE