Both the Desert Road and the alternate route along State Highway Four through to National Park were closed, Radio New Zealand reported.
Slips were causing problems for drivers on State Highway One in the Hurunui District.
Severe winds along the Johnsonville/Porirua motorway were making driving extremely dangerous. Police were asking motorcyclists to avoid the road. Black ice was making the trek across the Rimutaka Hill Road near Wellington trickier than usual on Sunday morning.
