The privileges committee last night issued a damning decision against New Zealand First leader Winston Peters, finding that he knowingly filed a false return to Parliament when he failed to declare a $100,000 donation from billionaire Owen Glenn.
It has wide cross-party support, opposed only by Mr Peters' party and Labour.
The finding means the committee did not believe Mr Peters or his lawyer Brian Henry when they said Mr Peters found out about the 2005 donation only on July 18 this year.
A majority of the committee recommended in the report that Parliament formally censure Mr Peters and that he be required to submit an accurate return to the Registrar of Pecuniary Interests.
Mr Peters responded last night by saying the finding had "echoes of Zimbabwe".
He thanked the committee members who applied themselves "fairly and neutrally" to the hearings.
"However a majority lined up along political party lines and insisted I was guilty before and during the hearings."
He said the committee had constructed a new test in September 2008 and applied it as though it were in effect in 2005.
"It therefore became a legal charade."
The committee's recommendations fall short of the maximum penalties the privileges committee could recommend - such as suspension or expulsion from Parliament, or even imprisonment.
But the fact a finding of contempt has been upheld, and such strong doubt cast on Mr Peters' word by his peers, is a damning penalty in itself.
The finding is backed by five of the seven parties represented on the privileges committee - National, Act, the Greens, the Maori Party and United Future
The broad cross-party support for the committee's finding will make it more difficult for Prime Minister Helen Clark to claim the committee was politically motivated.
Parliament will debate the report late this afternoon in what promises to be a highly charged debate.
Labour is expected to counter attacks by National on Mr Peters' honesty by questioning the honesty of National leader John Key, citing evidence showing he did not disclose how many TranzRail shares he once owned.
Speaker Margaret Wilson ordered the privileges committee inquiry after Mr Peters on July 18 that Mr Henry had just told him that Mr Glenn had donated to his legal costs.
That followed publication in the Herald the week before of emails between Mr Glenn and his public relations consultant in New Zealand, asking if he should deny giving to New Zealand First when he had done so.
The committee's task was to determine whether Mr Peters should have declared the donation as a gift in the 2006 register of pecuniary interests. But to decide that, it also had to decide when he knew about it.
Mr Peters told the committee that Mr Henry, acting on the advice of an unnamed client, asked Mr Glenn in late 2005 to help pay the Tauranga electoral petition's legal costs.
The MP said he never discussed money with Mr Glenn.
The committee heard from Mr Peters and Mr Henry and then - on a narrow vote, opposed by Labour and New Zealand First - decided to invite Mr Glenn to appear.
His evidence, of phone and email records, strongly suggested that Mr Peters had discussed money with him.
After Mr Glenn's evidence, Mr Peters and Mr Henry re-appeared before the committee. Both said they could not recall the conversation they had had just before Mr Henry sent details of his bank account to Mr Glenn.
A minority of the committee said they could not "dismiss the argument put forward by Mr Peters, which was that the conversation covered a number of topics but that money was not mentioned".
* "Contempt" is a term that covers all sorts of conducts that Parliament deems worthy of censure.