A thick blanket of fog over Adelaide has caused delays for travellers.

Heavy fog has impacted multiple domestic and international flights trying to leave and arrive at the airport.

Nearly every flight scheduled to arrive at the airport this morning was delayed by at least 30 minutes, with some pushed back by an hour and a half, according to the airport’s website.

The fog has also impacted departure times.

Qantas flight QF674 from Adelaide to Melbourne was scheduled to leave at 8.00am, but is now estimated to take off at 9.45am.

Air Asia flight QZ421 from Adelaide to Denpasar has been delayed by more than four hours, first scheduled to leave at 7.05am it will now leave at 11.10am.

Dozens of other flights have also been impacted. 

Delays appear to be reducing as the morning continues, but people picking up travellers arriving at the airport are urged to stay up to date with the latest arrival information.

There is also low visibility on roads, with police urging drivers to take care.