International Criminal Court chief prosecutor Karim Khan. ICC-CPI handout photo

(UPDATED) International Criminal Court chief prosecutor Karim Khan, being probed for alleged misconduct, is stepping down temporarily, his office announced on Friday.

Khan "communicated his decision to take leave until the end" of the UN internal investigation, and his deputy prosecutors will run the office in his absence, it said in a statement.

The governing body of the ICC earlier announced an external investigation into alleged misconduct by Khan, who has denied the allegations.

Khan hit the headlines last year when he sought ICC arrest warrants for Israeli Prime Minister Benjamin Netanyahu, former defence minister Yoav Gallant, and three top Hamas leaders.

Khan is also the chief prosecutor in the crimes against humanity allegations against detained former Philippine president Rodrigo Duterte.

The president of the Assembly of States Parties (ASP), Paivi Kaukoranta, said an external probe was needed "in order to ensure a fully independent, impartial and fair process."

The 54-year-old Briton said he welcomed the investigation and "the opportunity to engage in this process".

"I will be continuing all other functions as prosecutor, in line with my mandate, across situations addressed by the International Criminal Court," Khan said.

Khan has reportedly been accused of sexual misconduct towards a member of his office, but he has said there was "no truth to suggestions" of such behaviour.

"It was with deep sadness that I understood reports of misconduct were to be aired publicly in relation to me," Khan said in a statement emailed to AFP at the time.

The ICC has not yet made its decision on whether to grant the warrants he sought against the two senior Israeli politicians and the Hamas leaders.

Khan also sought and obtained an ICC warrant for Russian President Vladimir Putin of Russia, which promptly slapped arrest warrants on the prosecutor himself.

Khan has courted controversy throughout a career that has included stints defending Liberia's former president Charles Taylor against allegations of war crimes in Sierra Leone.

Other high-profile clients have included Kenya's President William Ruto in a crimes-against-humanity case at the ICC that was eventually dropped, and the son of late Libyan leader Moamer Kadhafi, Seif al-Islam.

Khan has fiercely defended the independence of the office of the ICC prosecutor, warning critics not to threaten him or they may find themselves in hot legal water.

He noted in his statement denying the allegations that "this is a moment in which myself and the International Criminal Court are subject to a wide range of attacks and threats."

Seated in The Hague, the ICC investigates and prosecutes genocide, war crimes, crimes against humanity and the crime of aggression.

Khan was born in Scotland and studied undergraduate law at King's College, London.

His father was Pakistani, his mother British and he is a member of the minority Ahmadiyya Muslim sect.

He became a practising lawyer in 1992, and went on to cut his teeth in international law at the former Yugoslav and Rwandan war crimes courts from 1997 to 2000.

He later represented survivors and relatives of victims of the 1970s Khmer Rouge regime in Cambodia at its UN-backed court in the late 2000s.

His other roles have included a stint at The Hague-based Special Tribunal for Lebanon, set up to bring to justice the killers of Lebanese ex-PM Rafic Hariri in 2005.

DUTERTE ARREST

Duterte was arrested on March 11  on his arrival from Hong Kong at the request of the ICC as part of its probe into his "war on drugs" that defined his presidency.

The ICC warrant for Duterte's arrest said that as president, the 80-year-old Duterte allegedly created, funded, and armed death squads that carried out murders of purported drug users and dealers.

He was brought to The Hague in the Netherlands on the same day he was arrested.

Duterte on March 14 appeared via video link before ICC judges. He is set to attend a September 23 hearing to confirm the charges against him.