The Court of Appeal has overturned a decision blocking National MP Murray McCully's access to court files the media were able to view, labelling the decision of the first judge "plainly wrong".
Mr McCully appealed against High Court Justice John Wild's decision, arguing it set a dangerous precedent for access
to future files by politicians.
Justice Wild's position was supported by Attorney General Michael Cullen, who was represented by Crown Law in the Appeal Court.
The file includes affidavits which will be used in a legal challenge by the Whangamata Marina Society next week against Conservation Minister Chris Carter's decision to prevent Whangamata's marina development.
Justice Wild found Mr McCully had not proved he had a "genuine or proper" interest in the file and he could not rule out the possibility the MP would use the material for "political purposes".
"This would run roughshod over the principle that Parliament and its members should refrain from commenting on matters before the court."
Mr McCully argued that as National's conservation spokesman his interest in keeping abreast of such matters was genuine and that Parliament's own rules acted to ensure MPs didn't act in contempt of court.
He also argued it was ridiculous that he could gain an understanding of the files only by reading what the media chose to report was in them.
The Appeal Court comprised Justices Grant Hammond, Rodney Hansen and Ron Young.
Justice Hammond, presiding, said in the judgment it was the first time such a matter had been heard in the Appeal Court.
While judges could restrict access to files, "we think in this instance, the High Court judge was plainly wrong."
Mr McCully had both a proper and genuine interest in the files as an MP and a conservation spokesman, the court believed.
"Parliament is entirely in control of its own processes.
"Mr McCully might or might not, according to the operative rules of Parliament, be able to use whatever information he gleans from the court file, in the House of Representatives. But Parliament is master of its own House."
