United Future leader Peter Dunne yesterday lashed out at Auditor-General Kevin Brady and former Solicitor-General Terence Arnold, QC.
He accused them of besmirching the reputations of MPs because of the way they wrote their reports on parliamentary election spending.
Most MPs were acting under what they understood the rules to be, Mr Dunne said. "To now have people off to one side effectively besmirching the reputation of all is unacceptable."
A more reasonable course would have been for the Auditor-General and Solicitor-General to have spoken to the parties to set out the issues and discuss how to resolve them.
Instead, their focus was extreme expenditure, and that led to the "bizarre" ruling by the Solicitor-General which drove the Auditor-General's draft report two weeks ago.
It found that much of the parliamentary expenditure by parties in the three months before last year's election was unlawful. Mr Arnold sent his opinion in April this year after it was requested by the Auditor-General.
Mr Dunne said the former Solicitor-General - now a Court of Appeal judge - "didn't even have the courtesy to come and talk to anyone about what actually happened, how the system worked".
"He just sat there in splendid isolation, made his ruling then skived off to the Court of Appeal."
Mr Dunne said it was ironic that one of the country's leading law officers appeared to have forgotten the concept of natural justice.
The MP's comments can be added to strong criticism against the reports from politicians including Prime Minister Helen Clark and New Zealand First leader Winston Peters.
Mr Dunne would not say how much the Auditor-General had found his party's liability to be - the Herald understands it is about $40,000 of nearly $1 million in total - but he has challenged the finding.
The party leader rejected a suggestion that he was putting pressure on the Auditor-General to try to get a more favourable final report.
"I'm not trying to monster anyone. We have all had our integrity slurred by this, yet no one bothered to come along and say, 'Look, these are the things causing me concern, this is where I'm heading, can you please explain what is going on'."
While Mr Dunne believes his own party's expenditure was within the rules understood at the time, he is not convinced that Labour's $446,000 pledge card was.
"The notion of a little card setting out five or six key points that [they] stand for is arguably within the rules in terms of providing public information; producing it on the eve of a general election introduces a big question mark into that whole process."
Mr Dunne said the matter needed to be sorted out by people who knew how politics worked, not academics in an independent inquiry.
"You've got to have a system that recognises politics is about communication, people promoting ideas, and the funding that is advanced to political parties has got to recognise that."
He said the Parliamentary Service Commission, comprising the Speaker and MPs from every party, had ordered a review of parliamentary spending by Auckland executive John Goulter and former Cabinet ministers Doug Kidd and Margaret Shields, and that was an appropriate body to sort out rules.
Mr Dunne said he was advocating more bulk-funding for political parties, but with greater accountability and transparency.
He took issue with statements by Acting Solicitor-General Cheryl Gwyn over a private legal challenge to Labour's pledge card spending that Parliament's bureaucrats, the Parliamentary Service, did not have an opportunity to vet advertising expenditure before it was incurred, and had no statutory power of decision-making - merely administration.
If that was the law, Mr Dunne said, it was not the practise.
"Every advertisement we placed, or any other activity we undertook that was the subject of parliamentary funding, we had signed off in advance by the Parliamentary Service."
