The Philippine city of Davao was in party mode on Saturday to celebrate the election of its most famous son, Rodrigo Duterte, as the country's next president.

Rock bands and break dancers entertained the crowd, which began to build from mid-morning under overcast skies on the outskirts of the southern city of Davao.

The city of less than two million last month saw its long-time mayor Duterte win a landslide election victory. His six-year term as president starts on June 30.

The foul-mouthed 71-year-old swept the poll by more than six million votes on a campaign pledge to wipe out crime by killing tens of thousands of criminals.

His law-and-order pledges hypnotised millions of Filipinos hoping for quick solutions to the nation's deep-rooted problems of crime and corruption, analysts have said.

"I've always been a Duterte supporter because he knows how to discipline people, especially the youth," said mother-of-six Emma Abubakar, 50, wearing a red shirt with Duterte's name printed on it.

With the president-elect widely expected to appear briefly much later, there was tight security at the venue, with metal barriers separating the crowd from the stage.

All bags were also being searched about a kilometre (0.6-mile) from the concert venue, where police estimated around 100,000 people would gather through the day.

Duterte supporter Ronnel Bernales said he was taking advantage of the thanksgiving party to celebrate his political idol as well as to make some money.

"I came here as a supporter and for an opportunity to sell," the 28-year-old told AFP. He had already sold 10 of his 250-peso ($5.40) "Du30" shirts in less than an hour.

Vendors were also selling sun hats, key chains, and other memorabilia, some printed with Duterte's election campaign slogans.