All prisoners could be stripped of the right to vote under legislation to be debated in Parliament later this year.
Currently, prisoners serving a sentence of three years or more are disqualified from the electoral roll.
A bill by National MP Paul Quinn plans to extend the current law so that all prisoners serving a sentence of under three years will not be eligible to vote.
Mr Quinn says he introduced the bill because he believes prisoners have transgressed against society and should not be allowed to vote.
The bill will come before Parliament later this year. If passed, the law would revert to what it was before the recommendations of a 1986 Royal Commission on the electoral system.
ACT will support the bill and the Green Party is against. It says every New Zealand citizen should have the right to vote.
Labour says it will consider whether to support the bill at a caucus meeting next week.