A law and order lobby group hopes the High Court will hear a claim that denying Maori inmates the right to vote is a breach of the Treaty of Waitangi.
The Rethinking Crime and Punishment group is supporting the claim of inmate Arthur Taylor, who wants to take the argument to the High Court.
It says a 2010 law denying prisoners the right to vote was found by the Attorney-General to be inconsistent with the Bill of Rights, but its impact on the Treaty wasn't considered.
The group's director, Kim Workman, said Maori were extended all the rights and privileges of British subjects, which could make voting a Treaty right.
He said Maori were six times more likely than non-Maori to end up in prison, and therefore six times more likely to be deprived of the right to vote.
Mr Workman said the High Court had to decide whether it had jurisdiction over the legislation.