People travelling on the Central Plateau are being urged to take extreme care tonight and tomorrow morning as temperatures are expected to drop below freezing.
Icy road conditions forecast tonight are expected to last well into tomorrow morning.
The NZ Transport Agency's acting regional performance manager Mercedes Santos said the winter conditions were nothing new but arriving in May might surprise some travellers.
"Motorists can keep themselves safe by lowering their speed, increasing their following distances, and taking extra care when cornering," she said.
Ms Santos said icy conditions mean trips take longer and motorists should allow more time to travel.
"It is also a good idea to check your vehicle before setting off to ensure it is safe for travelling on wet and icy road conditions," she said.
"Check your tyres, brakes, windscreen wipers, lights and steering and ensure your vehicle has a current Warrant of Fitness."
Transport Agency contractors will be out laying de-icing chemicals and grit which will keep roads open but those options can't be used in rain and road closures are possible.
The roads to take extra care on are:
• SH1 (between Waiouru and Turangi)
• SH4 (between Owhango and Raetihi)
• SH46 (all of this route)
• SH47 (all of this route)
• SH49 (all of this route)
• the Napier-Taupo Road (SH5) and over the Waitui Saddle on SH41 east of Taumarunui.
For real time information on highway conditions and incidents visit www.nzta.govt.nz call 0800 4 HIGHWAYS or follow @nztawaibop on twitter.
