Thick fog shrouding Auckland this morning is causing travel chaos as nearly 70 flights are cancelled and delayed.
There are fresh fog warnings for parts of New Zealand tonight, after air travel was severely affected when fog blanketed our biggest city this morning.
Air New Zealand put out a media statement late this afternoon warning forecast weather conditions were likely to affect flight operations in the lower South Island this evening.
"Air New Zealand is advising customers booked to travel to or from ports such as Christchurch, Dunedin, Queenstown and Invercargill to consult the arrivals and departures information on the Air New Zealand website here for up to date schedule information."
No one from Jetstar could be reached for comment on whether their flights might be affected.
Metservice meteorologist Tom Adams said as well as the southern centres, fog was also possible overnight in Hamilton.
Auckland was likely to be spared, after nearly 120 flights were delayed or cancelled, and an international flight diverted, when thick fog blanketed the city this morning.
Fog restrictions were lifted by the middle of the day, but fog returned again briefly just before 1pm.
It had cleared an hour later, but passengers were warned to check their flights online as the backlog slowly cleared.
Metservice meteorologist Tom Adams told the Herald that the fog which returned to the airport this afternoon was remnants of that which blanketed the city this morning.
"It erodes through the day but there's still wispy dregs of it ... if there's wind it can get blown back in."
The fog was unlikely to return to Auckland overnight, but in Waikato and parts of the Central North Island, including Rotorua and Taupo, it was likely to return, Adams said.
Wind in Wellington would prevent it enveloping the capital.
At midday the airport said 77 flights had been delayed and 42 flights cancelled because of the fog.
An international flight from Brisbane was diverted to Wellington Airport because of the fog.
Much of Auckland has been shrouded in dense fog since it descended over the city just before 3am.
Skies cleared briefly over Manukau Harbour at 9am allowing the airport to lift fog restrictions, but it rolled back an hour later.
Alongside the weather delays, a truck breakdown on the Southern Motorway in a citybound lane during the morning rush hour caused further holdups with motorists sitting in a 30km crawl to town until well after 8.30am.
