Central Auckland this morning. Photo: RNZ
About 37 regional flights were cancelled and many others others delayed, with eight main trunk domestic flights also affected after restrictions were put in place at the airport just before 2am.
Fog restrictions were lifted later on Monday morning, and flights were departing, but passengers faced delays.
Auckland Airport said international flights were not affected.
MetService meteorologist Mmathapelo Makgabutlane said the fog could persist for a few hours.
It comes after severe thunderstorms at the weekend caused heavy rain and lightning over much of the country.
Aotearoa was struck by lightning almost 60,000 times.
Makgabutlane said a large weather system moved across the country on Saturday and Sunday.
