Jailhouse lawyer Arthur William Taylor is set to be released on parole in February after a decision this afternoon.
The parole board said the decision was made at a hearing this afternoon.
A full written decision outlining the Board's reasons will be available within the next two weeks.
Taylor is serving a 17-year cumulative sentence in the high-security A Block at Paremoremo, which was set to end in 2022.
Age 60, he has spent 39 of the past 46 years in prison, and has mounted several successful private prosecutions from behind bars.
He has an extensive history of offending stretching back to 1972, when he appeared in the Youth Court on a forgery charge.
He has accumulated more than 150 convictions, many involving dishonesty, and others for fraud, perverting the course of justice, escaping, arson, and aggravated robbery.
He has been denied parole several times, but until this decision was still deemed too dangerous to release.
He has been a campaigner for prisoners' right to vote, winning a court declaration that a 2010 law banning prisoners from voting was a breach of the Bill of Rights Act.
However, the Supreme Court has ruled the ban was lawfully passed by Parliament.
Taylor and the other appellants said they would seek to take their case to the United Nations.