"It's going to be a wet weekend for most," meteorologist Sarah Haddon said.
"The situation at the moment is that there's quite a complex low sitting in the Tasman Sea, and there's a moist band of air ahead of it, which is assisting with the front which is slowly moving towards New Zealand.
"Rain is starting to affect New Zealand already. Nelson is going to be continuously raining for quite awhile, which is why there's warnings out."
The front was slow moving, which would cause persistent rain, she said.
Invercargill and the Milford Sound would be the best spots to be, with patches of sun predicted.
The rest of the country could expect cloud and rain with temperatures hovering in the mid tens.
The rainiest part of the weekend for Auckland is Saturday night with the possibility of showers on Sunday.
North Islanders could expect a burst of wet weather, while those in the south would notice the rain's persistence, she said.
ROAD CLOSURES
On the West Coast speed restrictions are in place and state highway 6 was down to one lane near Iron Bridge, between Murchison and Inangahua junction, after a slip. Drivers could expect delays of up to 15 minutes.
In Canterbury, state highway one south of Kaikoura, between Peketa and Goose Bay reopened at 7am on Saturday. The road, on restricted hours throughout the week, is extending its access due to the Seafest festival.
Inland Route 70 is open and has a number of sites down to one lane from the previous weeks weather at Green burn due to a slip. Drivers can expect delays.