The Greens are adamant their talks with Labour are about a lot more than the number of seats they hold in Parliament.

Co-leaders James Shaw and Marama Davidson have fronted media after meeting today with Prime Minister Jacinda Ardern.

It's been suggested the Greens have no leverage, because Labour holds a majority.

But Davidson says her Party's spent three years working productively with Labour, and has experience that Labour acknowledges.

She says they've had fruitful discussions with the Prime Minister, but the only thing on the table was biscuits and coffee.

Davidson she says the whole starting point for them is making change in the areas of the climate, the environment and inequality.

ACT leader David Seymour believes the Greens' do have bargaining power, in their talks with Labour.

That's despite Labour not needing the Greens' seats to form a government.

Seymour says the Greens will be far too nervous to say goodbye to their staff and Ministerial salaries - so will make a deal.

And Seymour says Labour has a skills shortage, made worse by the loss of safe pairs of hands like New Zealand First's Ron Mark and Tracey Martin.

However, former Green MP Catherine Delahunty says she'd be very careful about the risk of being absorbed and crushed within that huge Labour dominance.

She says if they stand independently they could raise issues.

Delahunty says if they agreed to a confidence and supply arrangement, the problem is the Government doesn't need their vote so it becomes meaningless.