Snowfall warning for some parts of NZ

Some areas of New Zealand could be in for an early white Christmas. Photo / Getty

Some areas of New Zealand could be in for an early white Christmas with the MetService issuing a December snowfall warning.

Snow flurries are expected at Porters Pass in Canterbury tomorrow morning after a period of rain tonight.

Less than 1cm may accumulate at the summit of the road between 4am and 7am on Sunday morning, MetService said.

Meanwhile, a cold change is coming and even though it will be short-lived, it will come as a shock to the system to some areas, especially those seeing highs towards 30C this week.

Areas of the South Island including Canterbury, Dunedin and Invercargill will see temperatures dip to the mid-teens tomorrow until the middle of the week.

The North Island won't see many dramatic changes although some in the east will notice the cooler weather arriving early next week, WeatherWatch analyst Philip Duncan forecast.

"Probably the biggest change to the North Island will be some cooler mornings from Monday next week and lower humidity for a short time," Duncan said. "Daytime temperatures in northern centres like Auckland will likely be unaffected."