The Electoral Commission begins a publicity campaign this week about a referendum which will be held with the general election on 26 November.
The referendum will seek voters' views on support for MMP or a different electoral system. Voters will have four alternatives to choose from.
If a change is supported, another referendum may be held to choose between MMP and the most popular alternative.
If voters opt for MMP, the Commission will review it and look at possible changes.
Chief Electoral Officer Robert Peden says the first lot of pamphlets will have very basic information. The commission's website has more details.