The Government could be breaching more than just the Bill of Rights by not allowing Maori inmates to vote, law and order lobby group Rethinking Crime and Punishment says.
Inmate Arthur Taylor has taken a claim to the High Court that 2010 legislation denying prisoners the right to vote is a breach of the Treaty of Waitangi.
Rethinking Crime and Punishment director Kim Workman said he believed Taylor had a point, and that the impact of laws on the Treaty had never been considered.
It said about 4300 Maori inmates would be denied the right to vote at the next general election.
Mr Workman said that could impact who was elected in marginal seats such as Te Tai Tokerau, where a fifth of Maori inmates affiliate to.
Any close call in the electorate could come down to the numbers of Maori who had been denied the right to vote, and he said that, in a sense, was a Treaty right.
The High Court is yet to decide whether to hear Taylor's case.