MetService issued a heavy rain warning for Bay of Plenty east of Opotiki, and Gisborne north of Tolaga Bay from 11pm tonight to 11pm Sunday.
Up to 230mm of rain was expected to accumulate about the ranges, and 140 to 180mm to lower-lying areas.
MetService meteorologist April Clark said the place to be this weekend would be the South Island's West Coast, while everywhere else would see rain at some point.
This morning a front was passing over Taranaki and Auckland, moving towards Bay of Plenty and Gisborne.
Western areas would see some morning rain before clearing for a fine afternoon.
The front was forecast to slow over eastern Bay of Plenty and the East Cape bringing periods of heavy rain.
Clark said at this stage is was unclear exactly where would see the heaviest rain and how much could fall, but people in the area should stay updated with the weather forecast.
A low could develop on this trough and lie slow moving about Bay of Plenty and East Cape, encouraging strong to gale easterlies about Gisborne, Bay of Plenty and Hawkes Bay. The front was forecast to move away from the east coast Monday into Tuesday.
The upper North Island was in for a relatively dry weekend, with just some rain in areas exposed to the northeast.
The rest of the North Island could see some scattered showers, some heavy, over the weekend.
The South Island's east coast was in for a "murky" end to the week, with low cloud and showers.
Nelson and Marlborough were in for a fine day, so too the West Coast after some morning showers.
This trend would continue into the weekend with fine weather in the west, and murky, drizzly weather in the east.
"The West Coast is going to be the place to be in the country this weekend, which you don't often hear," Clark said.
Northerlies would strengthen over the South Island on Monday ahead of another front, which was expected to spread rain over the West Coast on Tuesday.
Today's weather
Whangārei
Brief morning rain, then chance shower remaining as fine spells increase. Southwest change morning. 16C high, 5C overnight.
Auckland
Brief morning rain, then chance shower remaining as fine spells increase. Southwest change morning.15C high, 4C overnight.
Hamilton
Morning rain then chance afternoon shower as fine spells increase. Light winds. 15C high, 2C overnight.
Tauranga
Occasional rain developing morning and clearing afternoon. Northerly dying out afternoon. 14C high,
6C overnight.
New Plymouth Increasing fine spells. Chance shower until evening. Light winds. 14C high, 4C overnight.
Napier Occasional rain clearing late evening. Northerly gradually dying out. 15C high, 6C overnight.
Wellington Fine spells, and isolated showers clearing by evening. Gentle northerlies gradually dying out. 13C high, 6C overnight.
Nelson Sunny spells. Chance morning shower. Northeast breezes. 12C high, 2C overnight.
Christchurch Morning and evening low cloud or fog, otherwise fine. Light winds. 12C high, 5C overnight.
Dunedin Low cloud and periods of rain. Northeasterlies. 11C high, 9C overnight.
