Te Atatu in west Auckland is New Zealand's most marginal seat after last night's vote count.
Preliminary results show National's Angee Nicholas ahead of Labour's Phil Twyford by only 30 votes. Special votes are still to be counted.
Te Atatu was a brick in Labour's so-called "red wall" in West Auckland of Labour seats. Another former safe seat for Labour, New Lynn, is also extremely marginal with National ahead by 483 votes.
National campaign leader Chris Bishop has singled out the swing against Labour in Auckland as a key part of the election.
Speaking at a National Party press conference the morning after his party's victory, Bishop said Auckland had "swung hard".
He said the party had not expected to pick up Mt Roskill, where Carlos Cheung is leading Labour's Michael Wood by 1,429 votes, with special votes still to be counted.
"I'm not breaking any confidences, but we were not expecting to pick up Mt Roskill.
"We had a great organisation behind Carlos, but were up against a hard-working local MP in Michael Wood."
He singled out Te Atatu as another good result in Auckland, and said the party had put in real efforts in south Auckland, traditionally a Labour stronghold, singling out Manurewa as having a strong campaign on the ground.
In order, New Zealand's most marginal seats - those with a margin of less than 1000 - are:
- Te Atatu - 30 votes (National candidate ahead)
- Nelson - 54 (National candidate ahead)
- Banks Peninsula - 83 (National candidate ahead)
- Mt Albert - 106 (Labour candidate ahead)
- New Lynn - 483 (National candidate ahead)
- Te Tai Tokerau - 487 (Labour candidate ahead)
- Tāmaki-Makaurau - 495 (Labour candidate ahead)
- Rongotai - 792 (Green candidate ahead)
- West Coast-Tasman - 915 (National candidate ahead)