Louise Nicholas' credibility was repeatedly attacked in the High Court at Auckland yesterday when a former flatmate was said to have seen her having consensual sex with policemen she alleges raped her 20 years ago.

A defence lawyer revealed that the flatmate had said Nicholas "certainly wasn't saying no" during sexual encounters with the policemen.

Mrs Nicholas has always claimed she was home alone when Assistant Commissioner Clint Rickards or Brad Shipton visited her Corlett St flat in Rotorua between 1985 and 1986.

Yesterday, however, Rickards' lawyer, John Haigh, QC, questioned her about statements by the flatmate describing the atmosphere at the house as friendly and saying Mrs Nicholas never looked upset when the officers left.

Rickards and former policemen Shipton and Bob Schollum face 20 charges between them including rape, indecent assault and sexual violation.

Mr Haigh said the flatmate, who cannot be named, said she had come home one day and seen Mrs Nicholas having sex with Shipton or Schollum.

"To me she certainly wasn't saying no," the woman said. "Whenever the fellows called, they were always welcomed into the house. There was always a friendly atmosphere of laughing and joking."

She recalled one day when Mrs Nicholas had been in one room with Schollum or Rickards and she was in the lounge having sex with Shipton.

"It is possible Louise and I then swapped partners but I have no specific memory of it," her statement said.

She also said Mrs Nicholas never seemed upset when the men left or unhappy they were there.

In court yesterday, Mrs Nicholas repeatedly told Mr Haigh her flatmate's recollection was different from hers. She was home alone when Rickards and Shipton came around.

Mr Haigh: "She records that on one occasion she came into your bedroom and you were having sex with one or other of Mr Shipton or Mr Schollum and she lurked around the bottom of the bed."

Mrs Nicholas: "No, it did not happen."

She alleges the three men forced her to have group sex and she was indecently assaulted with a police baton in January 1986.

She says Schollum had picked her up as she walked home from work, taking her to a police house in Rutland St.

Mr Haigh asked why she did not refuse the ride, refuse to go into the house or seek help afterwards. He said Rickards' defence was that she simply fabricated the whole incident.

"I didn't want to walk up those stairs. I didn't want to get out of that car. I knew what was going to happen. I knew there was going to be group sex with these men again and I had no control over that. That had been stripped from me ages ago," she said.

Mr Haigh: "Why didn't you walk home?"

Mrs Nicholas: "And then what?...they're going to come back again as they had been. These guys are cops; I feared them; I didn't want what was going to happen."

Abuse had been part of her life since she was a 13-year-old growing up in Murupara, she said.

The court heard that she had made allegations against four officers working at the police station during that time.

She said the conditioning of her life was that if she made complaints, nothing would happen.

"Why didn't you tell your mother?" Mr Haigh asked.

"I didn't want to tell anybody about the Rutland St incident. I thought that no one would believe me," she said.

Mr Haigh suggested she was deliberately trying to destroy Rickards and was enjoying the media attention since her case was highlighted two years ago.

She said that 2 years ago she was approached by a reporter to tell her story. The reporter showed her documents, statements and job sheets which showed she had been "duped something shocking".

Shipton's defence counsel, Bill Nabney, asked her about a party in 1986 where Schollum and Shipton had given her a ride home, claiming they had consensual sex with her in the car.

"That definitely did not happen," she said.

Paul Mabey, QC, questioned her about a schoolteacher who claimed Mrs Nicholas had told her she had been raped by a group of Maori on horseback.

Mrs Nicholas said the teacher's recollection was wrong.

He questioned her about a statement where she said she had got drunk and had consensual sex with Schollum at a house in Kusab St.

Mr Mabey said Schollum bought the house in Kusab St in February 1986, after the alleged Rutland St incident.

"It's in the statement. I must have said it but I don't remember having sex in Kusab St," she said.

Mr Mabey questioned her about her brother Peter's wedding in February 1993 where Schollum was invited and was filming guests. He asked her if she had danced with Schollum that day or flirted with him.

"No, I definitely would not, thank you."

Did she remember lifting up her skirt and showing him her suspender belt? Mr Mabey asked.

"Is it on the video? No I did not."

Mrs Nicholas' family, including her mother and brother, are expected to start giving evidence today.