The Green Party has ruled out forming a government with the National Party after the election.
The Greens have been measuring the policies, programmes and public statements of the two major parties against a list of 12 criteria.
The list included questions about how Labour and National will work to reduce oil dependence, improve public transport, food security and the protection of public healthcare.
Greens co-leader Jeanette Fitzsimons says the outcome of its assessment was that it would prefer to work with the Labour Party.
And she says it could not form a government or go into a confidence and supply arrangement with National, saying a National-led government would take New Zealand in the wrong direction.
"We could not form a government with the National Party or vote confidence and supply with a National government."
"If National were to become the government anyway, regardless of that, we would still look for areas of common ground, where we could work with them to make their policies greener," Ms Fitzsimons says. "We have done that with successive governments, even when we have been voting against them."
No problem - Labour
Labour Party leader Helen Clark says there would be no problem with a Green Party MP having a ministerial position in the next government, depending on how the numbers fall after the election.
Miss Clark says after the election Labour will look at what the various components of a possible Government could be.
She was asked at her weekly post-cabinet news conference whether or not the Greens would be in line for ministerial slots after the election.
Miss Clark replied there would be no problem with having the Greens at the cabinet table, and there was not last time, but the voters would decide who gets into Parliament and in what numbers.
Not good for growth - National
National Party leader John Key says a Labour, New Zealand First and Greens coalition government would not encourage economic growth.
Mr Key says the Greens have an environmental focus over and above everything else, which comes at a tremendous price.
He also says Labour and the Greens can now be seen as a bloc when people go to the polls.
New Zealand First Leader Winston Peters would not be drawn on whether he would work with the Greens.