Prime Minister Helen Clark made a stinging attack on Act leader Rodney Hide as a "smear merchant", after he accused Associate Education Minister David Benson-Pope of irregular discipline practices when he was a teacher.
She fears Mr Hide is setting a tone of muckraking for the election campaign.
Mr Benson-Pope is now seeking legal advice over an interview on National Radio yesterday of an unnamed man who claimed that when he was 14 he was caned so hard by the former teacher, who was dean of his form, that it drew blood.
The man claimed Mr Benson-Pope laughed as he caned him.
Mr Benson-Pope was also accused of throwing tennis balls at students to keep them quiet, binding the hands of a pupil and putting a tennis ball in his mouth; and smacking a pupil with the back of his hand sufficiently hard to make his nose bleed.
Mr Benson-Pope rejected the allegations and called them "disgraceful" and part of a "scurrilous muck-raking exercise".
He has also been supported by his former principal and the present principal of his old school, Bayfield High in Dunedin.
Mr Benson-Pope refused to comment yesterday. A spokesman said it was business as usual as he undertook a tour of Christchurch.
Mr Hide and National MP Judith Collins posed the allegations as questions under parliamentary privilege on Thursday.
Helen Clark said late yesterday she would not be responding to anonymous allegations on the radio. But earlier in an interview on Radio Live she said what the MPs had done was "utterly reprehensible".
It appears that Mr Benson-Pope’s job is under no threat at present. But Helen Clark would be faced with a difficult decision if the former pupils did make public or official complaints. Mr Hide said he accepted Mr Benson-Pope’s assurances the claims were wrong - to not accept them could attract a privilege case being taken against him. But he rejected allegations that he was indulging in gutter-politics unbecoming of a leader.
Mr Benson-Pope was a secondary school teacher for 24 years, most of them at Bayfield High in Dunedin.
Mr Hide said he was first approached by a former student in 2000 but did not think it was an issue. Then the same person approached him , soon after Mr Benson-Pope became Education Minister and he raised other issues that had concerned him.
Mr Hide said that it was not the pending election that prompted the timing of this week’s questions but the fact Mr Benson-Pope had received local media coverage for an anti-bullying initiative.
Meanwhile, the president of the Post Primary Teachers Association, Debbie Te Whaiti, said that in such circumstances it was important that natural justice prevailed for both the former teacher and former pupil.