"We have a front moving onto the South Island travelling northeast over the country, bringing rain to the South Island's West Coast with a heavy rain watch in place from [Sunday] morning to Monday," Clark said.
"But if the cloud lingers it will at least mean it'll be a bit warmer. The east coast doesn't get the rain so badly, though."
The front would begin to move over the North Island on Monday, bringing rain to western areas.
Tuesday would see the front weaken over the North Island with scattered rain north of Taupo but mainly fine elsewhere. It was a similar story for the South Island.
However, another front was brewing to the west which could bring another batch of rain later this week," Clark said.
Meanwhile, the Desert Road was the only highway route across the Central Plateau which had yet to re-open yesterday.
More than 2200 homes on the central North Island's Powerco network were without electricity late yesterday, including about 1500 in Rangitikei and some 500 in Manawatu.
Eastland Network said several hundred homes on its East Coast network were also without power.
- Additional reporting: Newstalk ZB