Anti-establishment firebrand Rodrigo Duterte has claimed a huge win in the Philippine presidential elections after an incendiary campaign dominated by his profanity-laced vows to kill criminals.

Key points: Rodrigo Duterte's campaign dominated by vow to kill criminals

Rodrigo Duterte's campaign dominated by vow to kill criminals Recently caused uproar by joking he wanted to rape murdered Australian missionary

Recently caused uproar by joking he wanted to rape murdered Australian missionary Departing President Benigno Aquino has warned the nation of succumbing to a dictatorship

Mr Duterte, the longtime mayor of the southern city of Davao, hypnotised millions with his vows of brutal but quick solutions to the nation's twin plagues of crime and poverty, which many believed had worsened despite strong economic growth in recent years.

And after a record turnout of voters in Monday's elections, Mr Duterte scored a commanding victory, according to data released by the PPCRV, a Catholic Church-run poll monitor accredited by the government to tally the votes.

With nearly 90 per cent of the vote counted early on Tuesday morning, Mr Duterte had an insurmountable lead of 5.92 million votes over his nearest rival, administration candidate Mar Roxas.

"It's with humility, extreme humility, that I accept this, the mandate of the people," Mr Duterte said as the results came in.

"What I can promise you is that I will do my very best not just in my waking hours but even in my sleep."

Mr Duterte had 38.65 per cent of the vote, with Mr Roxas on 23.16 per cent, according to PPCRV.

Mr Roxas wished the new president success as he conceded on Tuesday after an unofficial tally showed him trailing by over 6 million votes.

Senator Grace Poe, the adopted daughter of movie stars, had already conceded just after midnight in third spot with 21.71 per cent.

"As a staunch supporter of electoral reform, I have a firm belief in the voice and sentiment of our people. I honour the result of our elections," Ms Poe told reporters in Manila.

"I congratulate Mayor Rodrigo Duterte and pledge my support in working to heal our land and to unite our people toward the continued development of our country."

In the Philippines, a winner is decided simply by whomever gets the most votes.

Early results suggest that his vice-president will likely be Ferdinand "Bong Bong" Marcos, the son of the late dictator.

Duterte uproar over Australian missionary rape joke

Mr Duterte, a pugnacious 71-year-old, surged from outsider to the top of surveys with cuss-filled vows to kill tens of thousands of criminals, threats to establish one-man rule if politicians disobeyed him and promises to embrace communist rebels.

He also boasted repeatedly about his Viagra-fuelled affairs, while promising voters his mistresses would not cost a lot because he kept them in cheap boarding houses and took them to short-stay hotels for sex.

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Mr Duterte had caused further disgust in international diplomatic circles in recent weeks with a joke that he wanted to rape a "beautiful" Australian missionary, who was killed in a 1989 Philippine prison riot.

"They raped all of the women ... there was this Australian lay minister ... when they took them out ... I saw her face and I thought, 'Son of a bitch. What a pity ... they raped her, they all lined up. I was mad she was raped but she was so beautiful. I thought, the mayor should have been first," Mr Duterte told a crowd of laughing supporters at a campaign rally.

Reports from the period, backed by Philippines media, name the Australian missionary as 36-year-old Jacqueline Hamill. Four other hostages were killed in the incident.

Departing President Benigno Aquino, whose mother led the democracy movement that ousted Ferdinand Marcos three decades ago, had warned repeatedly the nation was at risk of succumbing to another dictatorship.

"I need your help to stop the return of terror in our land. I cannot do it alone," Mr Aquino said in an appeal to voters in a final rally on Saturday in Manila for Mr Roxas, his preferred successor and fellow Liberal Party stalwart.

In his final rally on Saturday, Mr Duterte repeated to tens of thousands of cheering fans his plans to end crime within six months of starting his presidency.

"Forget the laws on human rights," said Mr Duterte, who has been accused of running vigilante death squads in Davao.

"If I make it to the presidential palace, I will do just what I did as mayor. You drug pushers, hold-up men and do-nothings, you better go out.

"Because as the mayor, I'd kill you."

Sorry, this video has expired Anti-establishment firebrand Rodrigo Duterte claims huge win in Philippine election

ABC/wires