Travel problems have eased on roads in the lower North Island on Saturday following bad weather.
Severe surface flooding on State Highway 2 in Hutt Valley on northbound lanes between Normandale lights and Normandale has receded, though warning signs are still in place.
Grays Road, between the Paekakariki Hill Road and State Highway 1 at Plimmerton, has now reopened.
The northbound lane of State Highway 3 near Ratana, south of Wanganui, is open and clear of slip debris.
In the central North Island, a blocked drain 3km south of Whakapapa village has closed a section of State Highway 48 in National Park.
Whanganui River warning
Residents in Wanganui are being warned about the potential flooding of the Whanganui River.
Horizons Regional Council says heavy rainfall has increased the water level, and several sites along the river may suffer surface flooding.
The council is monitoring the situation and expects the river level to peak in the Wanganui township between 4am and 5am on Sunday.
It says there is a possbility some roads may be closed between Saturday 5pm and midnight.
Heavy downpours, wind gusts
MetService says the area around Mt Taranaki received 100mm of rain in the 24 hours to 6am on Saturday, and 60mm fell in Milford Sound.
Lower Hutt received 26mm of rain between 4am and 6am on Saturday.
In Kaikoura, Föhn winds brought an unusually high winter temperature of 21°C degrees at 1am on Saturday, with humidity as low as 10% to 15%.
MetService says wind gusts along the east coasts of the North and South Islands reached 120kmh.
Transit is warning drivers to take extreme care on Arthur's Pass and Lewis Pass in the South Island, and to exercise caution on the North Island's Desert Road.
A ban on collecting shellfish and swimming in an area of Nelson is in place because of a sewage spill caused by flooding on Friday.