Former deputy Prime Minister Michael Cullen, who said publicly that he voted against MMP when it was introduced 15 years ago, has changed his mind about the voting system.
Dr Cullen told Nine to Noon that he will support retaining the Mixed Member Proportional system when a referendum is held alongside the general election on 26 November.
He said MMP has provided stable Government and greater representation of a range of viewpoints.
Dr Cullen said other systems used overseas would not be suitable in New Zealand, resulting in large electorates with vastly varying issues.
He said that is already a problem under MMP, with some elected representatives expected to cover a very large area.