Labour and New Zealand First last night denied attempting to pervert the course of justice over the privileges report on New Zealand First leader Winston Peters.
The serious accusation was made by Maori Party co-leader Pita Sharples - who also condemned Mr Peters' attacks on the Maori Party.
The accusations follow Tuesday's majority vote of censure by Parliament against Mr Peters for knowingly filing a false return of pecuniary interests, notably a $100,000 donation for his legal expenses from Monaco-based billionaire Owen Glenn.
The Maori Party held the balance of power on the vote in the House and it supported the censure motion.
If it had changed its vote and joined Labour and New Zealand First, it could have blocked it.
Dr Sharples said a minister telephoned him twice - on Sunday and on Monday - to try to persuade the Maori Party to oppose the censure motion.
He also said a New Zealand First staff member had sought to influence MP Te Ururoa Flavell - who was on the privileges committee - during a meeting.
"Both Tariana Turia and myself were disgusted with this kind of activity, aimed at perverting the course of justice and fair play."
Mr Peters said that was a "guilty reaction" from the Maori Party to its position on the privileges committee.
Parties try to persuade each other to their viewpoints all the time, but Prime Minister Helen Clark expressed concern at any "politicisation" of the committee.
That would have made any lobbying by Labour hypocritical.
Maori Affairs Minister Parekura Horomia admitted he had telephoned Dr Sharples on Sunday and on Monday but said that that was not out of the ordinary. The subject of the call was a kura kaupapa (Maori language primary school). He acknowledged they had discussed the Peters case but denied trying to persuade the Maori Party to change its mind.
"No I didn't. They are big enough to make their own decisions."
Mr Horomia said Dr Sharples had asked what the censure motion meant.
Mr Horomia said he had explained that Labour was supporting Mr Peters as "an elder statesman" in the Parliament - and on the evidence.
Mr Peters said in a statement that among discussions with the Maori Party too numerous to quantify, it had misconstrued one as having attempted to pressure them.
The admission that they could be pressured was unworthy of them.
In Parliament on Tuesday Mr Peters attacked the Maori Party for "selling out".
Dr Sharples said the Maori Party caucus was unanimous in supporting the privileges committee findings. "An attack on our credibility over this issue by Winston is totally out of order, and without any substance at all."