United Future leader Peter Dunne says this has been one of the nastiest weeks in his nearly 30-year political career.
On Friday, Mr Dunne resigned a government minister following the release of an inquiry into the leaking of a highly sensitive report into the Government's spy agency.
Prime Minister John Key ordered the inquiry into illegal surveillance and the current operations of the Government Communications Security Bureau (GCSB) after a reporter from Fairfax Media was shown a copy of the report in April this year, a week before Mr Key was due to release it.
Inquiry head David Henry says Peter Dunne had not fully co-operated with requests made to him during the inquiry, relating to emails between the MP and the reporter to whom the report was leaked.
Mr Henry said Mr Dunne gave the inquiry an edited version of 86 email exchanges which covered arrangements for them to meet and the official release of the Kitteridge report. Mr Dunne denies being the source of the leak.
Last week, United Future asked the Electoral Commission to be formally deregistered because it could not guarantee that it had 500 paid-up members.
Parliament's Speaker David Carter ruled on Thursday that United Future remained recognised as a political party as it should be given time to put the matter right. The Speaker's ruling means the party is still entitled to receive $100,000 in leadership funding while it sorts out its registration.
New Zealand First leader Winston Peters deplored the Speaker's decision. "That is simply Third World banana republic type of decision-making and we won't accept it."
Mr Peters told Radio New Zealand's Morning Report programme he does not accept that Mr Cater acted within the law and New Zealand First will press him to legally justify his decision.
Peter Dunne says the ruling is reasonable and denies the accusation he's been treated leniently because his party supports National.
"This has been probably the nastiest week of my entire political career. This is extremely bitter and unpleasant but to cave into it - I think that would be the worst thing."
Mr Dunne says it has only happened because United Future was upfront with the Electoral Commission. "I think the challenge would be for some of those other parties to submit their membership to a similar sort of scrutiny that we've been prepared to submit ours."
The Labour Party has asked the Auditor-General to urgently consider United Future's parliamentary funding. Finance spokesperson David Parker told Morning Report the interpretation by the Speaker is contrived and makes no sense, given United Future's deregisration.
Leader of the House Gerry Brownlee says the Speaker's decision is fair, and opposition parties ought to grow up and stop politicking.
United Future says it will be able to file for re-registration early next week, but the Electoral Commission will take six to eight weeks before approving it.
An expert in constitutional law, Graeme Edgeler, says the Standing Order related to United Future's funding is unclear.
He told Morning Report he initially believed Peter Dunne was entitled to keep the money and he still holds that view, but the law could be interpreted in a different way and should be clarified.
Mr Edgeler says he believes the important issue is the fact that Peter Dunne was the leader of a registered party when he was elected, and that party still exists, even though it's been deregistered.
Chief Electoral Officer Robert Peden says parties applying to the Electoral Commission must meet statutory requirements including providing party membership records and consent from the party's auditor.
He says membership records are then checked, which can be a lengthy process.