The general election will be held on 26 November. A referendum will also be held on the electoral system and whether people want to keep MMP or change to another method.
Radio New Zealand political reporter Julian Robins profiles the Single Transferable Vote system.
Voters in the upcoming referendum on the electoral system will have two proportional options to consider - the current MMP (Mixed Member Proportional) and the Single Transferable Vote system.
STV is the system used to elect the Australian Senate and also used in Ireland.
Of all the systems up for consideration in the referendum, Single Transferrable Vote arguably delivers the most power to individual voters to decide who is elected.
It's a system of proportional representation - but rather than rely on MMP-style party lists, it is based upon multi-member electorates with up to seven MPs elected in a single constituency.
The head of the School of Politics at University College Dublin, David Farrell, says STV has usually delivered Ireland strong, multi-party government.
"In the early 1980s, we had three elections in 18 months because we couldn't get an overall majority or a coalition that was stable. But that was less to do with the electoral system and more to do with the way electoral politics was panning out. On the whole, we've had perfectly stable government."
Under STV, there would be 24 to 30 electorates, each with between three and seven MPs, with parties allowed to stand multiple candidates. Voters would either rank the candidates in their preferred order, or vote for a ranking published in advance by a political party.
The rankings are used to calculate which candidates reach the necessary quota of votes to get elected, as Nigel Roberts from Victoria University in Wellington explains:
"If the candidate you vote for gets far more votes than they need to be elected, that candidate's surplus will be distributed to the second preference of that candidate's voters. Likewise, if a candidate ... is eliminated from the count the second and third preferences will be taken into account."
Richard Mulgan, the emeritus professor at Australian National University, says in theory, STV puts a lot of power in the hands of voters - but not necessarily in practice.
"What happens almost universally in Australia is that the parties are allowed to rank candidates according to their own party machinations, and then the voters just go in and tick one box ... and so in fact, you get just as much party power."
Professor Mulgan says the 1986 Royal Commission on the Electoral System, of which he was a member, decided not to back STV in part because of what they observed in Ireland.
He says under STV there can be a lot of internal fighting and much effort spent in people trying to secure their political base at home. "This, we felt, meant that MPs were not able to give enough time to national issues in parliament."
Pressure for electoral reform is building in Ireland. David Farrell says that is largely a reflection of the recent financial and economic crisis.
"We are in the worst crisis in the history of our state and part of the blame has been quite correctly attached to the failure of our political institutions.
One of the reasons why the electoral reform is now high on the agenda here is because many of our politicians blame the electoral system for the fact that our legislators are spending far too much time doing constituency service and then legislating in the parliament."
Mr Farrell says changing the electoral system in Ireland would not fix the country's woes, but there is growing support for a move towards a version of MMP.
