A new campaign has been launched against the MMP voting system.
Campaigners say it allows too many list MPs, rejected by the electorate, to get into Parliament anyway.
A referendum on the voting system will be held with the general election on 26 November.
It will ask whether voters want to retain MMP and will offer four other voting systems from which to choose if voters opt for change.
The group Vote for Change says it wants a system that results in fewer MPs who lose their electorate seats coming back into Parliament on party lists.
But Campaign for MMP says that is a weak argument because it is parties that decide who stands as an electorate MP and who will go on the party list and in what order.
Vote for Change has not yet endorsed an alternative to MMP. Spokesperson Jordan Williams says it wants to wait until it has a large membership and then will work with members to decide which voting system is the fairest.
The campaign's founding members include a former mayor of Waitakere, Bob Harvey, and former Labour MP Michael Bassett.
Vote for Change is being funded by its members and individual supporters and says it is not party political.