A severe weather warning has been issued as a deep low brings gales and heavy rain to the upper and central North Island and parts of the South.
People are being warned to take extra precautions and look out for rapidly rising rivers and streams, surface flooding and slips in affected areas.
A low forming over the Tasman Sea is spreading an active front over the North, bringing heavy rain to Northland, Auckland and Bay of Plenty for the next two days, said MetService forecaster Philippa Murdoch
"With that we are expecting Northland, Auckland and the Bay of Plenty to get some heavy rain and there could be thunder storms with that as well."
Heavy rain and severe gale warnings are in force for many areas.
A downpour is expected to develop in the eastern ranges of Waikato, Bay of Plenty and western Nelson this evening, and continue until Monday afternoon.
Between 11pm Sunday and 3pm Monday 80-120mm of rain was expected, with the Kaimai Ranges and the ranges of the Bay of Plenty due to be most affected.
A southeast flow is also expected to bring heavy rain to the far south of Fiordland from about midday today, easing tonight.
Heavy rainfall is also expected west of Motueka tomorrow and in Waitaki, Dunedin and Clutha districts on Monday.
The wet weather would mean a slight drop in temperatures with Northland, Auckland, Waikato and Bay of Plenty regions expected to hit a 14 degrees, said Ms Murdoch.
Tomorrow rain is expected to become heavy in eastern Otago as the southeasterlies spread north.
Severe gusts are expected in exposed parts of Fiordland on Monday. Winds could reach 130km/h - strong enough to damage trees and powerlines and make driving hazardous, warned MetService.
The winds are expected to begin to ease Tuesday morning.