Fog at Dunedin Airport has led to flight cancellations and delays.
Services to Auckland and Wellington have been cancelled, and an incoming flight from Christchurch.
Others, including a flight to Brisbane, have been delayed.
MetService said the airport recorded a low of -4 degrees overnight.
Queenstown also had a frosty start to the day with minus two degrees recorded.
⛄ Brrrr, it was a frigid start to the week in Ranfurly this morning, as the temperature dropped to -5.2°C!— NIWA Weather (@NiwaWeather) May 14, 2018
It's been a while since Ranfurly was that cold. In fact this morning's reading was the coldest temperature since 6 August 2017--a span of 281 days (just over 9 months). pic.twitter.com/oYq20zIt1m