Flights in and out of Palmerston North Airport have been delayed by fog.

Flights in and out of Palmerston North Airport were disrupted on Thursday due to lingering fog.

In the morning flights expected in from Nelson, Christchurch and Auckland were delayed with flights from Christchurch and Auckland also delayed from departing in the afternoon.

A flight to Auckland scheduled to leave at 6.25am was delayed until after 1pm.

Ryan Willoughby was scheduled to fly from Palmerston North to Auckland about 8.20am, but his Air New Zealand flight was cancelled.

READ MORE: Live: Weather wreaks havoc for travellers

The airline offered a bus service, but Willoughby was not keen on the day-long journey.

It was seven hour drive by car so it would definitely take longer by bus, he said.

For a lot of people the bus, which left about 10.45am, was the only option, Willoughby said.

"I'm trying to organise a car to drive up.."

The fog was not bad at ground level, but it looked pretty dense higher up, he said.

The cancellation meant Willoughby would have to find another way to Auckland before 5am Friday when he starts work.

Metservice meteorologist Peter Little said the bad weather that had been through Wellington had arrived in Palmerston North creating the low cloud issue.

"The good news is there is expected to be an improvement this morning.

"We are expecting things will brighten up during the remainder of the morning into the afternoon.

"But there could be low cloud and drizzle back again this evening."

Little said when there was weather like this they would often expect variation during the day, with an improvement while the sun is out and then cloud returning once the heat drops.

Palmerston North police Inspector Dave White urged drivers planning to make the journey by car to take care in the conditions.

"Travel with care and allow and understand it will take a considerable amount of time to get there so beware of fatigue."