The stormy weather and heavy rainfall which struck the bulk of the country yesterday should largely lift today - with the exception of some thunderstorms in the upper North Island.

Trees were downed, power cut, roads flooded and slips brought down amid the nasty weather on Saturday, with a flurry of crashes also attributed to the weather.

MetService initially issued a severe weather warning for today, but said this morning most of the warnings would be lifted.

There was still a chance of some heavy rainfall in the ranges in the eastern Bay of Plenty, it said.

The upper North Island  had a “moderate risk” of thunderstorms this afternoon. It would remain rainy, while the rest of the north island would  have few showers. The South Island was predicted to be largely fine.

As the week progresses, winter looks set to arrive right on cue with an icy blast bringing snow to low levels on both islands. WeatherWatch head analyst Philip Duncan said a cold southerly change would hit the country on Tuesday night - the eve of winter's first day.

"There will be snow on the ranges of both islands, there will be snow on all the ski fields across the country," he said. "There could even be snow in the Rimutakas and the Hawkes Bay ranges.

"We'll also see heavy cold rain on the east coast of the North Island, which is great for the farmers, although the cold isn't."

Heavy rain and winds caused a power outage in parts of Auckland yesterday, while two trees came down overnight, the Fire Service said.

Part of Johnsonville Shopping Centre north of Wellington was inundated and firefighters were called to flooded houses at Cooper's Beach in the Far North.

Emergency services were also called to a house near Taupo after a large macrocarpa went through the roof. A tree also fell on State Highway 30 at Awakeri, near Whakatane.

At least two vehicles collided at Paekakariki after one crossed the centre line near the intersection of SH1 and Beach Rd.

MetService recorded numerous lightning strikes in the North Island yesterday. More bad weather was expected overnight, including thunderstorms in the upper North Island.

"But there will be plenty of dry spells as well in between all the areas of rain," said Duncan.

In the South Island, an overnight snowstorm delivered some 35cm of snow to Canterbury's Mt Hutt yesterday, which ski area manager James McKenzie described as "a bit sticky but absolutely perfect for our initial base layer".