ACT would have 16 seats and could support National to form a government, the latest Taxpayers Union-Curia poll suggests.
The poll has ACT picking up 3.2 percentage points compared to the previous survey, bringing its support to 12.7 percent, almost equivalent to the 3.1 percentage points Labour lost, dropping to 33.8 percent.
National dropped 0.9 points to 35.6, the Greens gained 0.3 to 7 percent, and Te Pāti Māori gained 0.8 to 3.7.
This result would give National 46 seats and ACT 16 for a combined 62, comfortably able to form government. Labour would have 44 seats, with nine for the Greens and five for Te Pāti Māori assuming they won an electorate seat.
Labour leader Chris Hipkins' favourability rating fell 6 points to +22 percent, down 11 points from his +33 percent peak in March.
National's Christopher Luxon fell a further 1 point to -7 percent, his lowest score since he became leader. ACT leader David Seymour's favourability fell more dramatically, by 5 points, to -11 percent.
Of parties outside Parliament, New Zealand First was polling unchanged at 2.6 percent, TOP was up 0.9 percent to 1.7, the New Conservatives lost 0.1 percent support to 1.6 and Democracy NZ was down 1.3 points to 0.3 percent.
The survey of 1000 eligible voters was conducted between 2 May and 7 May, with 800 contacted by phone and 200 by online panel. Weighted results have a sampling error of +/-3.1 percent at the 95 percent confidence level.