MANILA (AFP) - Outgoing Philippine President Rodrigo Duterte could face international charges over his deadly drug war, but his daughter's thumping victory in the vice-presidential race shows his popularity remains sky-high.

Ms Sara Duterte-Carpio secured more than half the votes in Monday's (May 9) election, a ringing endorsement for the family name that has become a byword for brutality and impunity in the country.

More than 6,200 people have officially died in Mr Duterte's anti-narcotics campaign since he came to power in 2016, but rights groups estimate the true figure is in the tens of thousands.

While the deaths have been widely condemned and triggered an International Criminal Court probe, Mr Duterte's swift brand of justice struck a chord with many Filipinos fed up with the bureaucracy, corruption and dysfunction that affects their daily lives.

That popularity has rubbed off on his daughter, who supporters see as a safe pair of hands to continue his legacy - and protect him from potential criminal charges in the Philippines or abroad when he leaves office.

Ms Duterte-Carpio's success in the election on Monday cements the family's place at the centre of politics for another six years and ensures the Duterte name stays on the list of powerful political dynasties.

With her running mate Ferdinand Marcos Junior capturing the presidency, the two offspring of authoritarian leaders have been elevated to the nation's highest elected positions.

On the campaign trail, they embraced many of the elder Duterte's policies, alarming human rights activists, journalists and religious leaders.

Ms Duterte-Carpio, 43, had once been tipped to try to succeed her father in the presidential palace as voter surveys last year put her well in front of other possible contenders, including Mr Marcos Jr.

But she stunned political observers - and apparently her dad - by striking a deal with the son of the country's former dictator and instead running for the deputy's job.

When Ms Duterte-Carpio walked arm-in-arm with Mr Marcos Jr at a society wedding near Manila last November, Filipinos knew a political marriage had also been sealed.

The arrangement also brought together several powerful families that control swathes of the Philippines and have the means to direct voters to support their chosen candidate.

"I think we would have had an entirely different race had Sara Duterte decided to run for the presidency - probably Marcos would not have run at all," said political analyst Richard Heydarian, after a recent pre-election survey showed Mr Marcos Jr on track to win big.

While her role as vice-president will be largely ceremonial, it puts her within a heartbeat of the highest office and in pole position to run for president in six years' time.

She could also wield significant influence in the next administration.

The elder Mr Duterte will be hoping so as he prepares to step down on June 30, making him fair game for prosecution.

Quick temper

Until now, Ms Duterte-Carpio's career has been in lockstep with her father, following him into law and then succeeding him as mayor of Davao City on the southern island of Mindanao.

Known for her quick temper - she once repeatedly punched a court sheriff in front of TV cameras - she also has a fondness for big motorbikes and tattoos.

She is married and has three children nicknamed Sharkie, Stingray and Stonefish.

Ms Duterte-Carpio entered politics in 2007, serving three years as vice-mayor while her father was mayor of Davao - the family stronghold.

They swapped positions for the next three years and she again succeeded him as mayor in 2016 when he won the presidency.

Analysts say Ms Duterte-Carpio is not a carbon copy of her father, describing her as a more moderate version of a man known for his foul-mouthed tirades.

Yet some had questioned her broad appeal to voters, saying she lacked the charisma and humour of her father - key traits in a country where personality trumps policy.

Ms Duterte-Carpio has a fractious relationship with her dad, but has acted as first lady on some of his official trips overseas.

She defended him on the 2016 campaign trail after he sparked international outcry by joking about an Australian missionary who was raped and killed.

The younger Ms Duterte-Carpio disclosed in a since-deleted Instagram post: "Not a joke. I am a rape victim. But I will still vote for President Rodrigo Duterte."