The Green Party's wealth tax isn't a deal breaker.

Party co-leader James Shaw says the Party won't necessarily walk away from a coalition with Labour if its wealth tax isn't adopted.

Labour's ruled the tax out, but National doesn't think it will keep its word.

Shaw told Heather du Plessis-Allan the Party regularly discusses how it deals with Labour and thinks it works well.

Shaw says as a minor party, the Greens know they won't get everything they want.