Politicians are unlikely to make changes to MMP that will make their road into Parliament more difficult, and the public needs to pressure for improvement to the voting system, the Voters for Change group says.

A consultation paper was released today for an Electoral Commission review of the voting system, and chief electoral officer Robert Peden said public submissions would be open until May 31.

The commission's final report and recommendations will be given to Justice Minister Judith Collins on October 31, which Mr Peden said would give the Government enough time to legislate any changes before the 2014 election.

However, Voters for Change spokesman Jordan Williams said he was concerned MPs would ignore recommendations from the review if the public did not get involved.


"If not very many people engage in the review, if there's not much public discussion, then the politicians can easily side line it,'' he said.

"It depends what the recommended changes are ... but turkeys don't vote for an early Christmas, and politicians don't generally vote for a more accountable voting system.''

Voters for Change was particularly concerned with the current MMP thresholds, and called for the removal of what it called the "Epsom rule'' - the one-seat threshold that allows an electorate MP to bring in "coat-tail'' MPs, even if the party does not reach the required 5 per cent threshold.

Former Act leader Rodney Hide took a number of MPs into Parliament with him when he won the Epsom seat in 2005 and in 2008, despite the party not reaching the threshold.

New Zealand First received only 4.3 per cent of the party vote in 1999, but leader Winston Peters brought four MPs into Parliament after he held on to his Tauranga seat with a 63-vote margin.

The thresholds are among the topics the commission has already slated for discussion in the review, along with other controversial issues such as dual candidacy and who decides party lists.

Dual candidacy is responsible for so-called "back-door'' MPs. The controversial rule allows candidates to stand for an electorate and on a party list, meaning that in some cases an electorate MP can be thrown out by their local constituency but get back into Parliament on the list.

Labour's Clayton Cosgrove was saved by the rule last year, when he was voted out of his long-held Waimakariri seat, and National's Kate Wilkinson replaced him. Another notable case was former Greens co-leader Jeanette Fitzsimons, who won the Coromandel seat in 1999, lost it in the following election, but remained in Parliament on the list.

The consultation paper also specifically raises the issues of whether list MPs should be able to stand in by-elections, what should happen if a party wins more electorate seats that it is entitled to through the party vote, and the list to electorate seat ratio.

Mr Peden said the questions posed in the paper had been deliberately left reasonably open, and people were free to raise other issues.

"Anything that relates to how New Zealanders think we might improve MMP, we want to hear about,'' he said.

Issues around Maori representation, eligibility to vote, and other issues not directly relating to MMP will not be looked in the review.

Past MMP reviews had received mixed levels of response, ranging from 200 to 800 submissions, and Mr Peden said he expected submission hearings to be held in Auckland, Wellington and Christchurch. Depending on the demand, hearings could be held in more provincial areas as well.

About $1.6 million has been put aside for the review, and the funds are expected to predominantly be used for advertising.