A sna' />

A big majority of voters has been turned off by Prime Minister Helen Clark's "cancerous and corrosive" attack on National leader Don Brash.

A snap Herald DigiPoll survey found that 73.6 per cent of voters found the comment was "not okay".

Helen Clark used the phrase in retaliation for National's taunt that her Government was corrupt.

National's accusations that Labour was corrupt because it misused taxpayer money to fund its pledge card before last year's election has angered the party.

Last week Helen Clark said: "I can't state too strongly that Labour regards Dr Brash as a corrosive and cancerous person within the New Zealand political system."

She said the use of the word "corruption" against Labour was "intolerable and had no place in a Western democracy".

But voters did not react as badly to the use of the word "corrupt" as they did to the "cancerous" label.

Asked if Dr Brash was right to call Labour corrupt, 51.8 per cent said yes and 38.4 per cent said no.

The poll delivers an unmistakable thumbs-down message from voters when it comes to the personal attacks that have marked the political scene recently.

Following that tumultuous period, voters rate Dr Brash and Helen Clark similarly when it comes to honesty. Asked if Dr Brash is an honest person, 50.3 per cent said yes and 53.7 per cent said the same of the Prime Minister.

Asked who had handled themselves better amid the allegations and rumours, 43 per cent said Dr Brash and 29.4 per cent Helen Clark.

The poll made it clear that voters do not want to know about politicians' personal lives. A majority - 72.3 per cent - said they did not think the public ought to have been told about Dr Brash's alleged affair and 82.2 per cent said the public did not have a right to know the rumours about Helen Clark's husband, Professor Peter Davis.

The new poll of 500 voters - conducted on Friday, Saturday and Sunday - is the first to encompass allegations that private investigators were used to dig dirt on senior MPs from Labour and National.

It also covers Dr Brash's weekend admission that he has had private meetings with Exclusive Brethren members since last year's election.

The poll, with a margin of error of 4.4 per cent, shows National is emerging unscathed from the period of political mudslinging and revelations about the Brethren. It also shows that Dr Brash's rating as preferred Prime Minister is rising and Helen Clark's is falling.

Of decided voters, 45.7 per cent backed National and 38 per cent said they would vote for Labour - a lead of 7.7 points that is exactly the same as the Herald's poll last month. Helen Clark is still the country's preferred leader by a long way, but her support has slipped to 50.4 per cent from 52.4 per cent last month and 57 per cent in April.

Dr Brash's rating is moving in the opposite direction, despite his rumoured affair with businesswoman Diane Foreman and public marital difficulties.

His rating rises to 25.9 per cent from 22.4 per cent last month, and 51.6 per cent said he ought to remain as leader of the National Party.

Dr Brash said last night the poll indicated his party's support was holding well. "I think people are utterly fed up with Labour."

The election spending wrangle and the Taito Phillip Field inquiry were reasons for that, he said.

Education Minister Steve Maharey said last night the "small" poll did not reflect the full impact of the Brethren revelations. "The full import of that is still chugging through the system - we would expect to see some levelling up of this," he said.

He was commenting on the poll because Helen Clark is on leave, and believed to be skiing in the South Island with her husband.