The soaring popularity of National's John Key has pushed Helen Clark off her throne as preferred Prime Minister, a position she has held unassailed for eight years.
And Mr Key's role in getting a compromise on the anti-smacking bill may have been a big factor, something even Helen Clark concedes.
Thirty-two per cent of voters prefer Mr Key compared with 30 per cent for Helen Clark, according to last night's TV3 poll conducted by TNS.
His two-point lead reverses her nine-point lead in the same poll six weeks ago. She has lost seven points and Mr Key jumped four.
National also leads Labour in the TV3 poll by 48 per cent to 36, which would get it close to being a single-party majority government.
Labour's poor showing is expected to put more pressure on Finance Minister Michael Cullen to deliver a Budget this week that will reverse the retreating tide of support.
Helen Clark yesterday attributed the result to recent events, including the backlash over the anti-smacking bill, which outlaws physical punishment of children.
"Obviously the poll has picked up the backwash of section 59 [smacking], the gangs, Fisher & Paykel, interest rate rises," she said through a spokesman. "When you are in Government you cop the blame whether you are responsible or not."
Mr Key, who has been leader only since late November, believed the poll reflected a mood he had picked up all over the country that the Government did not have answers and it was "time for a change".
But he also believed his pursuit of a compromise on the anti-smacking bill contributed to his leap-frog over Helen Clark.
"I think one of the things people respected about Helen Clark is that she is a reasonably pragmatic leader and I think that is a trait they are looking for in anyone else who might replace her."
The week-long poll began on May 3, the day Mr Key bathed in publicity over the compromise which was announced at a joint press conference with Helen Clark.
The compromise was an explicit statement in law that the police had discretion not to prosecute minor and inconsequential offences if it was not in the public interest to do so.
The poll also followed two consecutive interest rate rises, and Fisher & Paykel's decision to move some of its laundry manufacturing to Thailand at the cost of 350 jobs.
The result is significant in that it is not only the first poll to nudge Helen Clark off her perch but it is the poll in which she proclaims the greatest faith - six weeks ago it was the only one that still had Labour in front.
Now it reflects the trends of other polls, such as the Herald's DigiPoll survey, which in February had Mr Key gaining fast on Helen Clark.
Helen Clark has been preferred Prime Minister in almost every poll since 1999 when she overtook incumbent Jenny Shipley.
In the TNS poll of decided voters on the party vote, National has 48 per cent (42 last time); Labour 36 (down from 44); New Zealand First 2.4 (1.2); the Greens 8 (6); Act 0.5 (1.3); United Future 0.6 (0.9); and the Maori Party 3.7 (2.7).
Translated to seats (if leaders with electorate seats kept them), National would have 59 seats, Labour 44, the Greens 10, the Maori Party five and one each for Act, United Future and the Progressives. National would need Act and United Future to govern, or the Maori Party.
The poll of 1000 eligible voters has a margin of error of 3.1 per cent.
No major poll until last night's has put Helen Clark behind the Leader of the Opposition.
Even when National overtook Labour after the 2004 Orewa speech by former leader Don Brash, she still maintained her pre-eminence as preferred Prime Minister.