Metservice says a weather front which has caused problems over much of the country will hit Auckland on Sunday afternoon.
The front, which has brought heavy rain and wind gusts up to 120 km per hour, has caused landslips and flooding, and seen rocks and trees blown onto roads.
Metservice says the front is maintaining its intensity as it moves north across the country.
Police have now downgraded high wind warnings for motorists in the lower North Island, saying the wind has reduced considerably.
Earlier on Sunday motorists were advised to delay travel on State Highway 1 near Bulls, in Manawatu, due to high winds and rain.
A series of small landslides on the Rimutaka Hill Road, near Wellington, also prompted a police warning to motorists.
There were reports of flooding on State Highway 6 near Cromwell in central Otago and rocks and trees blown onto state highways in Westland and Marlborough in the early hours of Sunday.
Heavy rain also forced the evacuation of the Omarama Camping Ground in the MacKenzie Basin after the Omarama Stream burst its banks.
State Highway 1 is closed at the Rangitata village in South Canterbury after rising floodwaters in the Rangitata River flooded farmland.
State Highway 83 from Otematata to Omarama is also closed due to flooding.
Further south, on State Highway 82, the Kurow - Hakarataramea bridge over the Waitaki River is closed and will reopen at 7am on Monday.
Metservice says another cold front is expected to start moving up the country on Monday.