Philippine President Rodrigo Duterte has reinforced his image as a maverick outsider focused on a brutal anti-crime war instead of the opulence of the presidential palace

President Rodrigo Duterte met with a businessman he accused of being one of the Philippines' top drug lords and threatened to kill him to his face.

In the bizarre meeting held Friday that evoked scenes from a gangster film, the hardline anti-crime president warned Peter Lim to steer clear of narcotics.

"I will execute you.... I will finish you off," Duterte said during the meeting.

A video of the sitdown was posted on a government YouTube channel Saturday with a caption identifying Lim as "one of the top drug lords in the triad involved in illegal drug operations in the country".

But the businessman denied that he was the alleged Chinese-Filipino drug dealer Peter Lim, who singled out by the president in an address on national television on July 7.

Peter Lim is a fairly common name in the Philippines, where part of the population claims ethnic Chinese descent.

The Peter Lim that Duterte met with said that since the address -- in which the president said "the moment he steps out of the plane, he will die" -- he has feared for his life.

"My family is really in a deep problem now in Cebu. We are getting all the threats," Lim said, referring to the central city where he runs a string of businesses.

But Duterte shot back: "I will not say I'm sorry because the reason you're here is you're a suspected drug lord."

Duterte built a fearsome anti-crime reputation as long-time mayor of the southern city of Davao, where he would read out the names of drug suspects on his local radio programme and the shamed personalities would later turn up dead on city streets.

He won the May election by landslide largely on a pledge to kill tens of thousands of drug suspects and other criminals.

Duterte has since publicly shamed police generals, politicians and private personalities whom he linked to narcotics, and a nationwide crackdown has seen nearly 400 drug suspects shot dead by police or suspected anti-crime vigilantes.

Human rights groups and opposition politicians have raised an outcry over the deadly anti-drugs campaign, but the government has insisted all the dead suspects had fought police and that the vigilante killing were being investigated.

During his meeting with Duterte, which took place at a drug enforcement agency office in the southern city of Davao, Lim denied any involvement in illegal drugs, but admitted he was investigated in 1997 for alleged links to narcotics.

He then pledged cooperation in Duterte's anti-crime campaign.

"Our nation is very lucky to have you. You're the only president who could save our nation. You really mean business," Lim added.