Denying New Zealand's prisoners the right to vote is inconsistent with the Bill of Rights, the country's highest court has ruled.
The Supreme Court released its judgment today upholding an earlier High Court decision saying the courts had jurisdiction to make a "declaration of inconsistency".
A majority of the five Supreme Court judges, comprising Chief Justice Sian Elias, Justice Susan Glazebrook and Justice Ellen France, dismissed the Attorney-General's appeal of the High Court's ruling.
Justice William Young and Justice Mark O'Regan dissented.
Arthur Taylor, known as a jailhouse lawyer for his litigation skills, and four inmates from Christchurch Women's Prison brought the case through New Zealand's courts after a 2010 law by the then-National Government banned all prisoners from voting.
The Supreme Court also unanimously allowed Taylor's cross-appeal and said he has standing after the Court of Appeal said he did not.
Prisoners could previously vote in elections if they were incarcerated for less than three years.
In 2015, the High Court issued a "declaration of inconsistency" with the Bill of Rights Act because it infringed on the voting rights of a New Zealander.
In his decision, Justice Paul Heath said the purpose of the declaration was to "draw to the attention of the New Zealand public that Parliament has enacted legislation consistent inconsistent with a fundamental right".
It was the first time the court has issued a declaration of inconsistency relating to the Bill of Rights.
The declaration alone, however, did not require Parliament to repeal the voting ban.
After the Supreme Court's decision, Justice Minister Andrew Little said the Government had already accepted it was right for the courts to declare legislation was inconsistent with the Bill of Rights.
"We think that what's more important, that once a declaration happens that there is a response from Parliament."
Little said there would be law changes which would compel Parliament to reconsider legislation in the face of such declarations and either confirm, amend, or repeal it.
But the issue of prisoner voting had not been discussed by Cabinet, he said.
"There is no Government view at all about prisoner voting legislation as it currently stands. We've been focused on the process for dealing with declarations by courts of inconsistencies with the Bill of Rights."
The Crown asked the Court of Appeal to overturn the declaration of inconsistency, but in May last year the Appeal Court upheld the decision.
The case went to the Chief Justice and the Supreme Court as the Crown attempted to overturn the declaration with at a hearing in March this year.
Solicitor-General Una Jagose argued prisoner voting rights were not an issue which should be decided by the courts.
"These matters are properly left to Parliament and the accountability to people at the ballot box. Because the future interpretation might well be different, for prisoner voting," she said.
"Now when the Bill of Rights Act was first enacted there was a complete ban on prisoner voting. And the history of prisoner voting tells us that originally, all sentenced prisoners were disqualified from voting.
"Then in 1975 all imprisoned people could vote. Then a blanket disenfranchisement went back on in 1977.
"It was in that context that the Bill of Rights Act was enacted. In 1993 it went back to a blanket ban.
"These matters are par excellence for Parliament to determine. I risk repeating myself, but it is bad for our democratic system of government for the court to formally criticise."
Jagose said while laws could be clarified by the courts, they should not be created or overturned there.
Taylor, appearing via audio-visual link from prison where he is currently serving a 17-year sentence for drug and violence charges, also presented his case to the court.
"I think the question should be phrased, does the Bill of Rights give me the right to vote?" he said.
"In my submission, your Honour, it does."
Taylor, who has spent some four decades behind bars, wanted the Supreme Court to again uphold Justice Heath's ruling.
Despite not forcing a law change, Taylor said such a ruling would still be powerful.
"The utility of a declaration of inconsistency has got real practical use," he added.
"It brings it to public notice, including politicians, that there is inconsistency here."
In a second part to the prisoner voting rights debate the Supreme Court heard whether the right to vote is entrenched in electoral law, meaning to pass legislation to take away the right needs a vote of more than 75 per cent of the House of Representatives or more than 50 per cent in a referendum.
In today's decision, Justice Glazebrook and Justice France said their starting point was the need to provide a remedy for action inconsistent with the Bill of Rights to ensure it was effective.
The courts could draw on a range of remedies including a declaration, they said.
The Bill of Rights, they observed, applies to the legislative branch and there would be no other effective remedy available in the present case.
Justice Glazebrook and Justice France further noted the making of a declaration of inconsistency was within the role of the courts to make declarations about rights and status.
The two judges considered there was utility in the declaration to provide a formal declaration of prisoners' rights and status.
Chief Justice Elias largely agreed with Justice Glazebrook and Justice France.
A declaration recognised and vindicated Taylor and the prisoners' right to vote while not interfering with Parliament's ability to legislate in this way, she said.
Justice Young and Justice O'Regan accepted the declaration of inconsistency could be consistent with judicial function, but considered there was no utility in granting a declaration because it would not affect any legal rights.