A video that went viral on the internet shows Mr Duterte speaking at a campaign rally in Quezon City in Metro Manila about a two-day siege at a jail in Davao City, 1000 kilometres south-east of Manila, in 1989. Philippines presidential frontrunner Rodrigo Duterte. Credit:AP Thirty-six year-old Jacqueline Hamill, from Strahan in western Tasmania, was one of five missionaries murdered by a gang of inmates before troops stormed the jail, killing all 16 hostage-takers. Mr Duterte, who was then a local official, has claimed he ordered the storming of the jail. According to a transcript of the video published by the Rappler news website, Mr Duterte told the rally that he saw Ms Hamill's body brought out of the jail.

"I looked at her face – son of a bitch – what a waste. What came to mind was, they raped her, they lined up," he said. Philippine President Benigno Aquino III, right, shakes hands with US Defence Secretary Ash Carter last week. Credit:AP "I was angry because she was raped, that's one thing … but she was so beautiful, the mayor should have been first. What a waste." The video ends at this point, although Mr Duterte appeared to be still talking. Mr Duterte has ridden a wave of discontent in the violence-wracked nation of 100 million people to lead repeated opinion polls over months, pledging to wipe out crime, threatening to shoot criminals, hang them using fishing line or drown them in Manila Bay.

"It's going to be bloody," he said of his putative presidency. "People will die." You feel it's a waste that you did not rape the Australian lay minister? You are a crazy maniac who doesn't respect women and doesn't deserve to be president. Vice-president Jejomar Binay, referring to rival presidential candidate Rodrigo Duterte Analysts say his surprise popularity in the majority Catholic country is similar to that of Donald Trump in the United States. He brags vthat he has two wives and two girlfriends. He told 10,000 supporters at a recent rally that he doesn't keep his paramours in posh condominiums, like other politicians spending public funds. "They just stay in boarding houses," he said. During rallies he has been seen kissing women and was later forced to apologise.

The women's group Gabriela denounced Mr Duterte's comments and demanded he apologise. "Rape, or any form of sexual abuse is not a joke, nor something to be trivialised in a joke, especially by those aspiring for the highest post in the land," the group said. Amid growing condemnation, Mr Duterte said he would not apologise for his remarks, even if it cost him the presidency. "I said it in the heat of anger," he said. "I'm sorry in general. I'm sorry to the Filipino people, it's my style, it's my mouth, I said it in anger – listen to the story behind it." He added: "It was not a joke. I said it in a narrative. I wasn't smiling."

Vice-President Jejomar Binay​, who is also running for president, issued a statement saying that anyone who laughs at the ultimate assault on the dignity of women should not be allowed to wield power. "You feel it's a waste that you did not rape the Australian lay minister," Mr Binay said, referring to Mr Duterte. "You are a crazy maniac who doesn't respect women and doesn't deserve to be president." Nick-named "Duterte Harry" after the famous Clint Eastwood character, Mr Duterte is a seven-times mayor of Davao who is credited with turning the one-time murder capital into one of the few Philippine cities with a reputation for law and order. He once told criminals they had two choices about how they left Davao: vertically or horizontally. "When I say leave Davao, you leave Davao. If you do not do that, you are dead," he told a recent heated political debate.

"If you do not know how to kill people and you're afraid to die, that's the problem, you cannot be president." Fifty-four million Filipinos are eligible to vote on May 9 to choose a president, vice-president and more than 18,000 legislators and local government officials. Since he was elected in 2010, President Benigno Aquino​ has presided over economic growth of more than six per cent, the country's best record in four decades. Mr Aquino is barred from re-contesting the election under the constitution.