Human rights groups are calling for an Edmonton constable accused of assault and racism to be removed from patrol duties after more allegations emerged during his disciplinary hearing this week.

The National Council of Canadian Muslims, the Alberta Muslim Public Affairs Council and Hate Free Yeg say Const. Nathan Downing should be reassigned to non-patrol duty while an investigation looks at his recent arrest of a witness who testified against him at a disciplinary hearing, the organizations said Friday in a joint news release.

"Having a police officer in an on-patrol role who is facing these allegations undermines the sense of trust and safety for community members, and as such, we support the call by black and Muslim communities to remove Constable Downing from patrol duties while the investigation is ongoing," wrote Abdul Malik with Hate Free Yeg.

"Because of the nature of the allegations that have been brought forward at this time, immediate action is needed," said Faisal Khan Suri, AMPAC president.

Downing faced a disciplinary hearing this week in relation to the March 2015 arrest of Nasser El Hallak, who accused the constable of repeatedly punching him and calling him the n-word and a f------ Muslim." Downing denies the allegations.

Downing, who denies the allegations, said he delivered one punch to El Hallak's face to gain control during a struggle after the man fled.

The constable has remained on the front lines since he was charged under the Police Act in March 2018 with unlawful or unnecessary exercise of authority, discreditable conduct and deceit.

On Wednesday, the hearing was adjourned after a key witness, Crystal Fox, said she had been arrested by Downing two weeks before she was scheduled to testify against Downing. Police are now investigating.

"It is not in the public interest for such an officer to be on the streets in such a position of authority while the investigation is ongoing," said Mustafa Farooq, NCCM executive director.

Mustafa Farooq with the National Council of Canadian Muslims says Downing should not be on patrol in a position of authority during the investigation. (Peter Evans/CBC)

Court records show Fox was charged on May 14 for driving with a suspended licence.

Fox lives in El Hallak's housing complex in northeast Edmonton. She testified that she saw Downing repeatedly punch El Hallak, who later spit up blood or vomited.

CBC has requested comment from Edmonton police.

In an unrelated disciplinary hearing in September 2015, Downing was found guilty of unlawful or unnecessary exercise of authority after hitting a fleeing suspect with his police van. The suspect's ankle was broken.

The disciplinary hearing has been adjourned until July 24.