Motorists have been warned by police to slow down in conditions known as "summer ice" as wet weather is expected to hit most of the North Island.
"Summer ice" conditions occur when rain combines with dust, oil and other substances that has built up on the roads to create slick conditions.
Roads in the Waikato up to Auckland and Northland could experience these conditions, NZTA said. Even a little rain after a period of dry weather can create these conditions, with the highest risk soon after it starts raining, the agency told RNZ.
Police advise drivers to take extra care on corners and increase following distance from vehicles in front.