The Greens would want a capital gains tax introduced in the first term, if they went into coalition with Labour, leader James Shaw says.
Labour's leader Jacinda Ardern has said its tax working group would look into a capital gains tax and if it recommended one, it would not take effect until after the 2020 election.
However, Green Party leader James Shaw told TVNZ's Q+A that a capital gains tax would be a priority in any coalition negotiations with Labour.
"There are a couple of things that I think we would like to push them on. One is a capital gains tax excluding the family home because we do have a real sense of urgency about the housing crisis."
But Ms Ardern said her timeline would not change.
"I've made my process very very clear and it's non-negotiable. We will undertake the work that we have set out as part of our tax working group.
"We will settle on solutions but they will not take effect until the 2021 tax year - if there are any changes at all. I'm sticking with that programme."
And New Zealand First leader Winston Peters has said a capital gains tax would be "off the table" in any coalition discussions with his party.