Former Finance Minister Ruth Richardson says MMP is corrosive for good decision-making.Former Finance Minister Ruth Richardson says MMP is corrosive for good decision-making.

New Zealand First leader Winston Peters at a public meeting in Henderson last month. Photo / Dean PurcellNew Zealand First leader Winston Peters at a public meeting in Henderson last month. Photo / Dean Purcell

The Labour-Alliance coalition Cabinet, pictured after the 1999 election, with Helen Clark (front) as Prime Minister and Jim Anderton (to her right) as Deputy Prime Minister.The Labour-Alliance coalition Cabinet, pictured after the 1999 election, with Helen Clark (front) as Prime Minister and Jim Anderton (to her right) as Deputy Prime Minister.

Ruth Richardson and Helen Clark both favour something similar to Britain's Office for Budget Responsibility. Ruth Richardson and Helen Clark both favour something similar to Britain’s Office for Budget Responsibility.

Dr Oliver Hartwich,  the executive director of the New Zealand Initiative, says political parties do not approach MMP properly.Dr Oliver Hartwich, the executive director of the New Zealand Initiative, says political parties do not approach MMP properly.

How MMP works

Reviews and votes on the electoral system

Who won power and when?