The Speaker, Jonathan Hunt, has been forced to defend his independence after refusing to bow to intense pressure to declare his Labour colleague Harry Duynhoven out of a job.

Mr Hunt said yesterday he was not "colluding" with the Labour-led Government, and had acted properly even though he would not say the New Plymouth MP had given up his seat when he breached the Electoral Act by restoring his Dutch nationality.

Opposition political parties have for two days argued that the same law required Mr Hunt, as Speaker, to promptly declare the seat empty, in line with the findings of the cross-party privileges committee that Mr Duynhoven had fallen foul of the act.

Instead, the Government this week moved Parliament into urgency to push through a special one-off retrospective law change, protecting Mr Duynhoven.

The law was passed yesterday, by 61 votes to 56, with Mr Hunt abstaining. It means Mr Duynhoven will remain an MP.

The privileges committee, comprising MPs from all parties, had said Mr Duynhoven effectively quit his seat by applying to have his Dutch nationality restored, in breach of the Electoral Act because it required him to declare some form of allegiance to a foreign state.

Only the three Labour MPs on the committee, Deputy Prime Minister Michael Cullen, Attorney-General Margaret Wilson and Cabinet minister Lianne Dalziel, disagreed.

Instead, Margaret Wilson said in Parliament yesterday that it was a valid if "courageous" decision to declare the law ambiguous.

But the rest of the committee accepted the advice of the Solicitor-General, Terence Arnold, that the law was quite clear.

The Electoral Act says a seat becomes vacant if an MP "does or concurs or adopts in any act" to become a subject or citizen of another power.

A majority of the privileges committee said that Mr Duynhoven breached the act, possibly twice, by filling in the forms to restore his Dutch nationality and then in June when Dutch authorities confirmed he had acquired it.

National and Act this week demanded that Mr Hunt declare Mr Duynhoven's seat vacant, without delay, which they said the Speaker was bound to do under the Electoral Act.

Instead, Mr Hunt said the committee's report would be debated by MPs in the future, while Labour swiftly moved to push through a change to the act suspending the provisions which Mr Duynhoven breached.

National's deputy leader, Roger Sowry, told Parliament there was a danger the Speaker's role was being used by the Government.

"That causes me a great deal of concern and pain because I, for one, believe in the integrity of this place."

Under the protection of parliamentary privilege, he reminded Mr Hunt that Speakers were judged according to their integrity and for standing up for the parliamentary process.

Mr Prebble said the Speaker should not be seen as allowing the Government to manipulate parliamentary business.

Under the sustained attack, Mr Hunt defended his role, and said he had acted completely properly.

"I am certainly not colluding with the Government on this issue, and I make that statement absolutely, absolutely."

He was entitled to defer taking action "for a short time" under byelection provisions of the Electoral Act and he would not delay a decision just to give the Government time to bring in a law change.

He said he would decide when Parliament debates the privileges committee report, which will not be until next week, whether the New Plymouth seat was vacant.