A wintry blast is expected to hit the South tonight and tomorrow, bringing snow to 300m in several areas.
MetService says a very cold southerly airstream is forecast to move onto the lower South island tonight and onto the North Island tomorrow.
Snow is expected to fall to 200m in Fiordland and to 300m in Southland and Otago this evening, and to 300m on Banks Peninsula tomorrow.
Snow could approach warning amounts down to 400m, the weather agency said.
NZ Transport Agency Otago/Southland journey manager Graeme Hall said motorists needed to be ready for this weather.
"We need everyone to drive to the conditions; to allow more time for their trip, be prepared for unexpected hazards and ensure their vehicle is winter fit, as crashes can result in more serious consequences," Mr Hall said.
"The margin for error on wet, slippery roads is tiny. Even the smallest mistakes when travelling in snow, ice and frost can in a split second, see you lose control of your vehicle, with often disastrous results."
