Driving in winter in New Zealand is for the most part no different to any other time. Indeed, winter can be a great time to travel with less traffic and clear days. Extra care does need to be taken in the some places where roads can be affected by snow and ice at times.
Take a little more care where there is potential for ice and avoid night time or early morning driving if possible. Icy road conditions are generally signposted, with regularly ice-affected corners permanently signposted and temporary conditions marked.
Some southern regions' roads can be affected by snow. But road conditions will be clearly signposted and, when necessary, roads will be closed. Main highways usually re-open within a few hours of a heavy snowfall after road crews clear them.
In winter you will need to carry snow chains to travel on some roads when they are likely to be affected by snow. These include some popular and recommended routes like the Crown Range road, between Queenstown and Wanaka, and the road to Milford Sound. Snow chains are available to hire when you collect your rental car.
Driving in winter can be very enjoyable. Quiet roads and clear days make for some of the best scenery. Simply adjust your driving to suit the conditions.