The Green Party has released a list of the criteria it will use to decide which party it will support after the election.
While the party has aligned itself with Labour in the past, it says that support cannot be taken for granted.
The 12-point list covers both social and environmental issues including questions about how Labour and National will work to reduce oil dependence, improve public transport, food security and the protection of public healthcare.
The Green Party co-leader, Russel Norman, says the party wants to be transparent about its approach and will assess the two main parties' policies as they are released.
He says the results of the analysis will be published so voters know how the party reached its decision, which will be made two weeks out from the election.