Dozens of flights in and out of Wellington airport were cancelled from Sunday afternoon due to low fog, disrupting hundreds of passengers days before Christmas.
MetService is warning of more disruptions on Monday as the sea fog may linger.
Jetstar was forced to cancel 10 flights on Sunday afternoon, while Air New Zealand cancelled almost 40 flights.
Air New Zealand says it expects flights will resume at 9am on Monday and the airline is investigating ways to provide additional capacity into Wellington to accommodate passengers who missed their flights on Sunday.
Jetstar says it will put on additional flights on Monday between Auckland and Wellington and Wellington and Christchurch.
It says there are also spare seats on its scheduled services.
A MetService spokesperson says the fog has now set in for the night and while there is a possibility it will lift on Monday, it may only be for a brief time in the morning.