More rain and high winds were expected on Tuesday, further hampering rescue efforts.
“Emergency services are working night and day, but unstable ground, floodwaters and closed roads are making things difficult,” said Emergency Management Minister Kieran McAnulty.
New Zealand Fire and Emergency Services said one firefighter is missing and another is in critical condition after a house collapsed in West Auckland.
“It’s been a tough night for the whole of the North Island, but it’s been particularly tough for fire and emergency,” said Kerry Gregory, chief executive of the fire service.
Hipkins said his thoughts were with the two firefighters involved and urged New Zealanders to put “safety first”.
Hipkins has pledged an aid package of 11.5 million New Zealand dollars ($7.25 million) to help with recovery efforts, but McNulty admitted the cost of the cleanup was spiraling.
“The honest answer is it’s not going to be cheap, but that’s not what we’re worried about right now,” he said.