Greens leader James Shaw says the party is very aware of losing support to Labour and it's one reason they didn't go into a full coalition.
In tonight's 1 NEWS Colmar Brunton poll, Labour has jumped nine points on its December poll result, to 48 per cent, its highest level in 15 years.
National has slipped three points since December to 43 per cent.
The Greens are down two per cent to five per cent, and New Zealand First is below the five per cent threshold at three per cent, down two this poll.
It's clear from the poll that Labour's rise is coming at the expense of its partners in Government, the Greens and New Zealand First.
"That is something that we are really cognisant of. That's one of the reasons we decided to go into a confidence and supply agreement rather than a full coalition," said James Shaw, Green Party leader.
Labour's surge in support comes after the coalition Government ticked off its 100 day policy target, and Prime Minister Jacinda Ardern's sure-footed and controversy-free visit to Waitangi.
Ms Ardern says she expects that over time "we will see our coalition partners lift in their numbers as well".
Outgoing National Party leader Bill English says, "For now they might put up with that. Later on it will get harder."
Meanwhile, the Maori Party and The Opportunities Party are unchanged on one per cent in this poll.
If the poll numbers were translated into seats in Parliament, Labour would have 59 seats and the Greens would have six, giving the centre left a majority of 65 seats.
National would have 54 seats, while ACT would have the one it currently holds.