Wellington Airport posted an update to Twitter, telling travellers to check its website for the latest updates on their flights.
Air New Zealand, Virgin, Qantas and Sounds Air flights from Melbourne, Sydney, Christchurch, Queenstown and other origins were all diverted from landing in the capital.
Farmer earlier said low fog that had moved over the city was affecting aircraft.
Flights would have around 500m of visibility as they descended into the fog above the airport, but this would reduce as they flew through the fog, she said.
Clouds were hanging as low as 200ft (61m) above the tarmac.
The cloud was expected to move towards the Hutt Valley as the afternoon wore on, but it may remain in the area until tomorrow.
Newshub reported most of Sunday evening's departures had been cancelled, but one flight was attempting to take off.
Three Jetstar flights between Auckland and Wellington had been cancelled due to the weather conditions, Newshub reported.
Air New Zealand and Wellington Airport have been contacted for comment.
