Ice is distrupting travel at Dunedin Airport.
No flights are landing or taking off at the airport.
Dunedin Airport spokeswoman Megan Crawford said there was ice on the runway and it was raining.
"It was 0 degrees Celsius an hour ago and it's still raining. We need a little bit more heat on the runway before we can get things moving again."
Flights inbound and outbound for Christchurch, Wellington and Auckland had been affected.
Flights affected include Air New Zealand arrivals NZ5057 from Christchurch and NZ5443 from Wellington, which were cancelled because they could not land due to the ice.
Four departing Air New Zealand flights had also been affected.
Two - NZ50162 bound for Christchurch at 8.20am and NZ5048 bound for Wellington at 9.10am - were cancelled.
Two more - NZ410 to Wellington and Auckland, due to depart at 6.25am, and NZ5012 to Christchurch, due to depart at 7.30am - have been delayed.
Full details are available on the airport's website.
Crawford said roads were also affected by ice.
"It's pretty bad. There's actually a police cordon turning people back at the turn-off to the airport [on State Highway 1]. Unless they really need to go south they're turning them back."
Wellington Airport spokeswoman Arpita Dutta said there were some delays caused by the situation in Dunedin. Full information was available on the airport's website.
"It's flights from the South Island, we've got no issues weather-wise here."
Christchurch Airport spokeswoman Yvonne Densem said delays were a result of weather at other airports.
"It's not a problem at our end."
According to the airport's website inbound and outbound Invercargill flights had been delayed.
An Auckland Airport spokeswoman said the airport was operating normally.
Roads closed
• State Highway 25 25A
• Tapu-Coroglen
• Kennedy Bay Roads Wade Road to the 309 Road.