The pair made the comments after a campaign rally in Auckland's K Rd this evening.
It is their last rally of the 2020 election period.
It comes after a week of attacks from National, which has been critical over the Greens' proposed wealth tax – a tax of 1 per cent on net wealth over $1m and 2 per cent on net wealth over $2m.
That is a tax that Ardern has ruled out a number of times this week.
Speaking to Newstalk ZB on Monday, Ardern said that the proposal for such a tax would not even make it to the negotiating table if Labour is able to form a government.
And today, Ardern went even further – saying that there would never be a wealth tax so long as she is Prime Minister.
Despite this, Shaw told media after the speech tonight that the policy was something the Greens would put up for discussion in any post-election talks.
"Let's have an election and then let's sit around the negotiating table and see what happens," he said.
He added that after the votes have been counted, it will be the Greens that decide what will be taken to the negotiation table.
Davidson said the fact that National has been hammering this policy so hard was a "sign of their desperation".
"It has become alarmingly clear that the priority of National, and the other smaller parties, is not to keep us safe … but to divide us, and to make us scared, in the pursuit of power," she said during her speech.
The rally comes just three days before polling closes.
The Greens are hovering just over 5 per cent – but have not dipped under that threshold in any polls so far.
In his speech, Shaw made something of a call to action to his supporters.
"At this election, I can confidently say that the Green Party is the only party putting forward proposals that are actually bold enough to meet the scale of the challenges we face."
And Davidson took it further: "Labour cannot govern alone."
"Unchallenged decisions can mean bad decisions, and with the Greens at the decision-making table, we'll make sure that we truly face the challenges we've been ignoring for too long."