Key Points:

A group of Auckland police officers have been accused of subjecting a motorist to a racist roadside interrogation - which resulted in one officer allegedly pulling down the man's pyjama pants and then calling him a "monkey".

The allegations - described by leading Queen's Counsel Peter Williams as the worst racial incident he has heard of in his legal career - have been referred to the Police Complaints Authority (PCA) following a formal complaint to Auckland police last week.

Williams has also formally complained to the Attorney General and says unless action is taken against the three officers he will seek punitive damages.

The claims cap off a difficult fortnight for police, already under fire over the Bazley report which resulted in an unprecedented apology to the public about historic police behaviour.

Police said the complainant's account of the events differed greatly from those of officers.

Police spokeswoman Noreen Hegarty told the Herald on Sunday the complainant, 29-year-old Auckland man David Newell, had been stopped on Monday evening after allegedly being clocked at 107km/h in a 50km/h zone and subsequently charged with refusing to provide a blood sample. Newell denies he was speeding.

Hegarty claimed that when confronted by police, Newell said his mother-in-law was a High Court judge and he was a Kenyan diplomat. He then pulled down his pyjama pants in front of the three officers and civilian observer who had been accompanying them on patrol, she said.

Newell, she claimed, was then told to pull his pants up before being handcuffed and put into the back of the police car.

Newell has rubbished the police version of events and has agreed to undergo a polygraph examination to prove he is telling the truth.

His lawyer, Christopher Reid, has also accused police of fabricating a story, saying the officers involved were going to extreme lengths to discredit his client.

If he had, in fact, removed his pyjama pants he would have been charged with indecent exposure, he said.

In a sworn affidavit, Newell - a policy analyst with the Franklin District Council - said on the evening he was stopped he had been making a quick trip to his local Pt Chevalier shops to buy nappies for his three-year-old daughter. At the time he had been wearing a loose-fitting top and pyjama bottoms with no underpants.

He was stopped by one officer and the civilian observer in a marked patrol car on Great North Rd - one male and a female - on suspicion of speeding and was told his vehicle would be searched, according to his affidavit. While that was happening, two other uniformed officers turned up in an unmarked car - another woman and another man.

Newell claimed that the male officer asked him where he was from, to which he replied north London in the UK. The officer, who had an English accent, told him: "we used to deal with you people all the time," a reference, Newell said, to the colour of his skin.

According to Newell's affidavit, he was then ushered to the side of the road and asked if he had been drinking. Newell replied he had had half a glass of beer at lunch with his partner Amber but nothing that evening.

Then suddenly and without warning, Newell claimed, the police officer with the English accent "whipped down" his pyjama pants, exposing his private parts to the other officers.

The officers were all giggling and making jokes related to black men and the size of his penis, according to his affidavit. He said he was also called a "black ****".

With Newell's pyjama pants still around his ankles, he said he was asked to undergo a breath screening test and despite two attempts he claimed police were unable to obtain a reading.

Newell bent down to pull up his pyjama pants and was then handcuffed and put in the back of the police car and taken to the Balmoral Police Station, according to the affidavit.

He claimed he was then unnecessarily brutalised and suffered cuts and bruises as he was taken from the car into the station by one of the female officers.

Once inside the station, he claimed, he was hit in the face by the officer with the English accent and called "a monkey". That officer, he said, refused to accept his word he did not have a criminal record, saying "all you people (black people) have convictions".

In his affidavit, Newell said he had been happy to undergo a blood test but had wanted to go home after the ordeal. As there had been little objection, he did so and made a formal complaint at Auckland Central Police Station the next day.

He told the Herald on Sunday yesterday he was still shocked by what had allegedly happened, could barely sleep and was undergoing counselling.

"It was such a violation, I couldn't believe it. I was humiliated when they pulled my pants down and exposed my private parts," he said. "I came to New Zealand because it was supposedly a great place to raise kids. The last thing I ever expected was this. "

Williams said he had spoken to Newell, who presented as a "highly credible young man", and was astonished police could have behaved in such a "disgusting inhumane" fashion.

The police spokesman confirmed Newell had been taken to Balmoral Police Station and had chosen not to engage the services of the duty solicitor, preferring instead to call his partner. He was then charged with refusing to supply a blood sample. He is due to appear in court later this month.