The son of Philippine drugs war madman Rodrigo Duterte is facing assault and threat charges as the powerful political clan teeters on the brink of collapse.

Paolo Duterte, 50, allegedly attacked a customer at a bar in the family's stronghold Davao City in Davao del Sur on February 23.

CCTV footage that emerged this month shows Paolo - who is re-running for congress - swaggering into the bar surrounded by his bodyguards. The furious politican then stomped over and squared up against another man, seen in the video sheepishly bowing his head in apology.

Paolo then raised his hand as he threatened to swing down what appeared to be a knife, before butting his head against the man several times.

Prosecutor General Richard Anthony Fadullon confirmed that the Department of Justice main office in Manila has received a copy of the complaint, filed by businessman Kristone John Patria.

He said: 'Paolo comes from an influential family in Davao City, which is why I did not immediately take action against him.'

The case comes just a week ahead of the country's midterm elections on May 12.

Paolo's sister, Vice President Sara Duterte, claimed Philippine president Ferdinand Marcos Jr. was behind the complaint.

She said on May 3: 'This administration has done nothing but politicise and smear their political opponents. You can all see that whenever something happens, this administration destroys their political rivals to cover up the real issues of society.'

The controversial but popular Sara had forged an alliance with Marcos Jr. that saw a landslide win in the 2022 national elections. However, their partnership has since unravelled over various clashes regarding issues such as diplomacy and the country's territorial dispute with China.

Marcos Jr., also known by his nickname 'Bongbong', is believed to be behind the dismantling of the powerful Duterte family amid the bitter fallout.

Sara is set to face an impeachment trial on July 30, while her father, bloodthirsty strongman Rodrigo Duterte, was arrested in March and shipped off to The Hague in the Netherlands to face trial for alleged crimes against humanity.