The announcement of Laila Harre as leader of the Internet Party again put the political focus on the high rate of abstention in the 2011 general election when more than a quarter of enrolled voters failed to cast a ballot.
Harre stated her party's main objective was to mobilise these no-shows, dubbed the "missing million". If this happens, it is likely the survival of the National-led government would be in doubt.
The missing million fall into two groups: the nearly 800,000 who registered to vote but didn't and the more than 200,000 Kiwis the Census tells us didn't even bother to enrol.
Given pro-active enrolment campaigns by the Electoral Commission and the fact that enrolment in New Zealand is compulsory, it's likely that the unenrolled group won't reduce by much. That still leaves the enrolled non-voters. Following the 2002 general election, the Labour Party set out to understand who made up the non-vote to develop strategies to mobilise at least some in 2005.
The party observed that the non-vote was highest in safe Labour electorates and lowest in safe National seats. After research, a number of conclusions were reached.
The non-vote is nearly impossible to poll by conventional methods.
As many as half the people contacted refuse to participate. It is likely that in this group the non-voters are to be found (or not found).
There is a strong correlation between income and non-voting. High levels of non-voting occur among those groups in the lowest income quartiles - Maori, Pasifika, beneficiaries and state house tenants.
Non-voters fall into three categories. There are those who will never vote for reasons of religious conviction, physical or mental incapacity or extreme age. In Australia, where voting is compulsory, this group makes up the 6 or 7 per cent who still don't vote.
The second group is best described as disengaged. They simply believe that politics has nothing to do with them or their lives, but can be motivated in certain circumstances.
In 2005, National's proposal to replace income-related rents with market rents in state houses motived a much larger proportion of state house occupants to vote than in 2002.
The third group is the most likely to vote in September. These people didn't bother voting in 2011 because they saw the outcome as a foregone conclusion. For these people to be motivated, most of whom would vote left, they need to be convinced a real contest is on. The challenge for the opposition parties is to become relevant to marginalised electors and to look like serious challengers.
Mike Williams is the former president of the Labour Party. The Herald on Sunday is publishing a range of views Out of Leftfield.