"Our domestic jet services - Boeing 737 and Airbus A320s - have been operating all day, while turbo-propelled aircraft which operate to the smaller regional centres have been delayed or cancelled. Jets have technology on board which allow them to operate in a  certain level of fog.''
A Jetstar spokesman said six of the airline's domestic flights had been cancelled today and one flight from Sydney had been diverted to Wellington.
Passengers had all been placed on other flights.
Fog is still causing problems at some of the North Island's smaller airports, with delays in Hamilton, Kerikeri, Rotorua and Tauranga.
One disgruntled passenger, who preferred not to be named, said she had been waiting at Auckland Airport for more than eight hours.
"My holiday's going really well so far.''