Wellington Airport was fully operational on Monday after fog cancelled four international flights to Australia earlier in the morning, and closed the airport for most of Sunday.

The fog lifted about at about 6.15am and Wellington Airport officials said they were hopeful that it would be business as usual for the rest of the day.

Air New Zealand had to cancel 130 flights and Origin Pacific cancelled 12 because of the fog.

A number of international flights were diverted to Auckland.