Senior minister Trevor Mallard has accused former Police Commissioner Peter Doone of being drunk the night in 1999 when the car in which he was a passenger was stopped by a constable with a breath-testing device.

Opposition MPs yesterday stepped up their calls for Prime Minister Helen Clark to release records of her conversation with the Sunday Star Times over the matter, and Act MP Richard Prebble suggested they could be used to blackmail her.

Mr Mallard made his claim in the House under parliamentary privilege amid mounting pressure on Helen Clark to release notes or a transcript of the confidential interview she gave to a reporter about what the commissioner had allegedly said that night.

Mr Mallard made his comments in response to National deputy leader Gerry Brownlee, who said he wanted to talk about things that were factual.

"No 1, he was drunk," Mr Mallard shouted.

"Let's get the facts right in this situation. Peter Doone, then Commissioner of Police, had been drinking," Mr Mallard said.

"He had been drinking for four hours.

"He got out of his car. He stopped the young constable who had a sniffer, who was about to breath test his partner who had also been drinking for four hours.

"He interfered with the young constable who had the sniffer."

Opposition parties saw Mr Mallard's attack as an attempt to deflect attention away from their own attacks on Helen Clark's integrity.

Mr Mallard and Helen Clark had several private conversations during question time ahead of his speech about the night in question.

There can be no doubt that she would have known about and authorised the nature of his speech.

The constable, Brett Main, did not conduct a breath test of the driver Robyn Johnstone, now Mrs Doone, after Mr Doone stepped out of the car and had a conversation with him.

Mr Doone's actions were the subject of two separate critical investigations. He eventually resigned after reaching a settlement with the Government.

Mr Doone sued the Sunday Star Times for claiming he had allegedly said "that won't be necessary" to the constable approaching the driver with the breath tester.

Mr Doone abandoned the action last week and said he would sue Helen Clark instead, having only recently found out her involvement.

The Sunday Star Times said its source was the police but that Helen Clark had confirmed the story.

But the phrase was not in the police report, which Helen Clark had at the time she spoke to the reporter. The police report said Mr Doone had told the constable "we'll be on our way" and added "or words to that effect".

Mr Mallard said in the House that the phrase used in the report had been Mr Doone's view of what was said - and that had been disputed by the constable.

The police report had made it clear that the two constables on duty were sober, said Mr Mallard. He said that at the time National had been critical of what happened. "And now what are they doing? They are defending the driver who had been drinking and the Commissioner of Police who interfered with a constable in the course of his duty."

The police report has Mrs Doone saying she had two or three small glasses of white wine and snacks during a function before the car was stopped.

Mr Doone said he had one or two bottles of Light Ice beer in the afternoon and two or three white wines in the evening and water and juice.

Helen Clark has told the House she would not have been able to confirm the words "that won't be necessary" because they were not in the report, and that she imagined they had been put to her by the reporter.

She is certain she would have confirmed that what was said was being contested.

National leader Don Brash told the House that many people believed the Sunday Star Times and its lawyers had tapes of the conversations with Helen Clark that would show her statements to be "utterly false".

He challenged her to allow the release of any such records.

Mr Prebble made a case for her to insist that whatever records Fairfax (publishers of the Sunday Star Times) had should be published.

"Is it not the position now that the Fairfax newspaper has said that it published the statement 'That won't be necessary,' because the Prime Minister confirmed that that statement was true, and that the Prime Minister has told the House that she made no such statement; and, if there are transcripts ... is she not now in the position where an overseas newspaper can blackmail the Prime Minister of New Zealand at any time in the future by threatening to release those transcripts?

"Is that not undesirable and should she not insist that the transcript be released so that the public is not in the position of thinking that an overseas newspaper is possibly blackmailing her?"

The Prime Minister answered by saying she was confident she drew the newspaper's attention to the fact that the facts were contested.