The career criminal, Arthur Taylor, has taken his legal battle challenging a ban on prisoner voting to this country's highest court.
The High Court and Court of Appeal have already ruled against them, but in December the Supreme Court agreed to give them one last hearing.
In 2010, Parliament passed a law preventing all sentenced prisoners from voting, regardless of the length of their sentence.
However, earlier electoral legislation allowed prisoners serving a jail term of less than three years to vote.
A lawyer for Taylor told the Supreme Court today the ban on prisoner voting was an "entrenched" part of the electoral law which required a 75 percent majority to pass, but when Parliament made the change, it did not have that many people in favour.
Francis Cooke QC said the law said every adult was qualified to be registered as an elector, which was consistent with the Bill of Rights.
He said the real question that arises in the case was whether Parliament had protected some but not all of the requirements to be a registered elector.
"If Parliament, by ordinary legislation, sought to say that only men could cast a vote that would be a breach of the protected right of all 18-year-olds to vote as Parliament has voted in universal suffrage.
"Equally a race-based system saying no Māori or Chinese person could vote couldn't be implemented without engaging the protected right in s74 as entrenched.
"It's a question of whether Parliament appreciated that this encroaches on what an earlier Parliament said should only change based on a specific majority. All I need to do is persuade the court the prisoner voting ban is on the wrong side of [that] line."
Mr Cooke told the Supreme Court that in upholding the prisoner voting ban, Parliament must have realised that was inconsistent with what a unanimous Parliament did in 1993 and for it to pass they had to deal with it in accordance with the entrenchment provisions, meaning a 75 percent majority was required for it to pass.
"What they are seeking is not constitutionally dramatic; all that will happen is it will go back to Parliament so it can address the issue.
"The Crown concedes the current electoral law is a breach of fundamental human rights. It also means New Zealand is in breach of its international obligations to those rights."
A lawyer representing the other prisoners taking the case, Richard Francois, said the removal of a prisoner from the electoral roll could affect their participation in future elections once they were released.
"Once people go back out into the community they don't necessarily go through re-registering, ... because they don't know they have to.
"They front up at an election and are told they're not registered. Or [it could be] because many coming out of prison don't have great literacy skills. And yet as soon as they go in [to prison] they're taken off it."
However the Solicitor-General, Una Jagose, told the Supreme Court the lower Courts rulings against the prisoners were correct.
She said their claim that the legislation's reference to 18 years as the voting age gave an entrenched right to vote was "incoherent and inconsistent with the Electoral Act as a whole".
Ms Jagose said that when he introduced the 1956 Electoral Act to Parliament, Sir John Marshall said the actions of Parliament at that time could not bind future parliaments.
The legislation was passed in order to safeguard the electoral system and the Electoral Act delivered the nuts and bolts of how such a system might run, she said.