The Antarctic polar blast is disrupting Air New Zealand flights to and from some South Island destinations.
It comes as south to southwest gale force winds are forecast to bring bitterly cold conditions across much of the South Island, according to MetService.
"Dunedin, Invercargill and Queenstown are experiencing strong winds, low cloud and snow causing cancellations into and out of these regions," Air New Zealand said in a statement.
"The challenging weather is expected to last through to tomorrow and the airline is working through recovery flights for impacted customers."
The airline is encouraging people booked to travel on affected flights transfer their travel to another date by managing their booking online.
"Air New Zealand’s contact centre is currently experiencing a high volume of calls due to the travel pause with Australia contributing to longer wait times.
"Customers booked to travel domestically today are advised to keep an eye on the Air New Zealand arrivals and departures page for the most up to date flight information. If travel is not urgent, customers can opt to hold their fares in credit. This can be done online."
The Interislander ferry has cancelled all its sailings for tomorrow as massive waves are predicted to hit the Cook Strait and Wellington's south coast from around 8:30am.
Motorists have been advised to drive to the conditions as road snow warnings have been issued for all the major passes throughout the South Island.