Explaining the MMP referendum
In 1993, voters opted to change from the traditional First Past the Post (FPP) electoral system to Mixed Member Proportional (MMP).
The first general election under the new system was held in 1996 and this year voters have a chance to say how they think it's going.
What is the referendum?
There are two questions. You will be asked whether you want to keep MMP or change to another electoral system. The second question asks which of four alternative systems you would prefer if MMP were to be scrapped. You should answer both questions, even if you want to retain MMP.
What are the options?
The four alternatives to MMP are FFP, Preferential Voting, Single Transferable Vote and Supplementary Member.
The different voting systems explained.
When will the result be known?
The results from advance votes will be announced on election night but the final result of the referendum will be released on December 10.
Why does the electoral system matter?
It affects how seats are distributed between parties based on the number of votes they get.
What happens if more than 50 per cent of people vote to keep MMP?
An independent review of the current system will be undertaken.
What happens if fewer than 50 per cent vote to keep MMP?
A second referendum will likely be held in 2014 offering the choice between MMP and the alternative system that receives the most votes this month. Parliament must agree to hold the second referendum.
What will be in the MMP review?
The review will be conducted by the Electoral Commission and recommend changes to MMP. It will consider the current 5 per cent threshold, whether voters should be able to change the order of candidates on a party's list and whether candidates should be able to stand in an electorate and on a party's list. It will not look at the number of MPs or the retention of the Maori seats.
Is the referendum binding?
No. Parliament does not have to accept the outcome of this referendum. But if it decides to hold the second referendum in 2014 that one will be binding.
When would the change happen?
If a majority of voters chose to change from MMP and an alternative system was chosen in 2014, the first election under that system would be in 2017.
If a review of MMP is held the Electoral Commission must report back to the Minister of Justice before October 31, 2012.
Where are the different systems used around the world?
Our MMP model is based on that used in Germany and a similar system is used in Scotland and Wales.
FPP was used in New Zealand from 1914 to 1993. It is still used in Britain and Canada.
Preferential Voting is used in the Australian federal election.
Single Transferable Vote is used here for some local government and district health board elections and is used in Ireland and Northern Ireland.
Supplementary Member is used in Japan. A version was originally adopted in many of the Eastern Bloc countries after the fall of the Soviet Union.
What are the party's positions on the referendum?
The two major political parties haven't taken official opinions but Prime Minister John Key personally supports Supplementary Member and Labour leader Phil Goff likes MMP. The Green and Maori Parties support MMP. The Act Party has no official position.