Most politicians prepared to come to MMP's 10th birthday party

She opposed MMP fearing it would lead to weak and unstable governments, but 10 years on Helen Clark says Labour has made it work and she wouldn't vote to change the system.

She believes MMP, which was first used in an election a decade ago today and which she didn't support preferring the status quo, has delivered more open and transparent systems of government and a more representative Parliament.

Green co-leader Russel Norman is another supporter, saying MMP provides an ideal mix of local and proportional representation.

He says select committees have become stronger and more proactive as a result, creating much greater scrutiny of legislation.

A spokesman for New Zealand First leader Winston Peters also points to the strengthened select committees as an example of effective MMP politics.

He says it creates a multi-party democracy, rather than a two party system, which while it might be more time consuming, can lead to better outcomes.

The party isn't promoting a new system - "MMP was the people's choice and we respect that" - but wants MP numbers reduced to 100.

United Future leader Peter Dunne says his party doesn't have a view on whether another electoral system would be better, and it supports another binding referendum on MMP.*

National remains committed to a referendum on MMP, arguing the public should decide whether it is the most appropriate system.

Leader Don Brash prefers the supplementary member system (SM).

Under SM the party vote delivers each party a share of only the 51 list seats, not of the whole House. So the small parties' hauls dive and National's and Labour's rise.

Dr Brash says: "It provides scope for minority views to be heard, but avoids the present system where very small parties can exert quite disproportionate influence in a situation where the two major parties are typically fairly evenly balanced."

Maori Party co-leader Tariana Turia says while MMP provides a mechanism by which Maori interests can be "effectively protected by Parliament, we know that our people have consistently expressed concern that the structure of the system itself is not necessarily consistent with the drive for rangatiratanga".

Mrs Turia says she believed "the electorate seats are the only truly elected seats in Parliament".

The parties maintained their differing stances on the Maori seats: Labour and the Greens say it is up to Maori, National wants them gone, United Future wants a discussion with Maori on a timetable for phasing them out and the Maori Party seeks to have them entrenched like the general seats.

NZ First supports a single franchise, but says any decision is "for the people to make".

Other issues being promoted or raised by parties include:

* United Future wants a four year term and a fixed election date.

* The Maori Party notes the Electoral Commission survey earlier this year on "Understanding MMP" says more education and information on the system needs to be targeted towards Maori and Pacific peoples, youth and those with lower levels of education.

* The Greens want party representatives removed from the Electoral Commission, the funding system changed to prevent large anonymous donations and consideration of state funding.

- Additional reporting NZPA

* An earlier version of this story said United Future did not support a referendum. Incorrect information was provided by Mr Dunne.