A high pressure system over New Zealand is expected to bring fine weather for most this week.

Sunshine is forecast for the Bay of Plenty for the entire week, except for Sunday when rain and westerly winds are expected to move in.

Further down the country, things are looking a bit wetter.

The MetService is forecasting a front to move slowly northwards over the South Island from late Wednesday bringing more heavy rain to the West Coast as we begin September.

Perhaps of even greater concern is that the front should also bring a period of rain for Tasman, Nelson and Marlborough from late Friday into Saturday, with heavy falls about the ranges likely to cause more problems in these already sodden regions.

"We could see over 300mm in the ranges of Westland later this week, and possibly 50 to 70mm in the ranges near Nelson and northern Marlborough," warns MetService Meteorologist Stephen Glassey.

"This amount of rain wouldn't normally cause too many problems in Nelson and Marlborough but because they have already had extreme amounts of rain recently it could lead to more slips."

Nelson and Blenheim have already beaten their wettest winters on record by considerable margins, getting almost three times their average for winter.

Nelson Airport has recorded over 700mm rain since the beginning of June, beating their previous record of 570mm in 1970.

Meanwhile, Woodbourne Airport in Blenheim has had around 560mm this winter beating their previous record of 377mm in 2010.

Orange Heavy Rain Warnings and Watches are likely to be issued for the West Coast, Tasman, Nelson and Marlborough regions in the coming days, says Stephen.

Elsewhere in New Zealand it is looking like a mostly settled week, with the eastern South Island expected to stay mostly dry, and the rain-bearing front not expected to reach the North Island until the weekend.

However, there will be a few showers in some regions before then.

"The warmer north to northwest winds ahead of the front will make it feel like spring in a few places, especially in the east of the South Island later this week. However, some colder temperatures are signalled across the country next week."

Image: MetService.