Flights still delayed as Sydney fog lifts

At least a dozen domestic flights and four international flights in and out of Sydney are still delayed after fog blanketed much of the city in the morning.

The thick fog which blanketed much of Sydney has lifted but some flights are still delayed. (AAP)

The thick fog which blanketed much of Sydney has lifted and road conditions have improved but more than a dozen flights are still delayed.

The Bureau of Meteorology issued an alert about the dangerous road conditions on Saturday morning with the fog affecting all Sydney suburbs.

The fog, which delayed more than 40 domestic flights and at least eight international flights in and out of Sydney in the morning, cleared by about 11am.

The bureau has now cancelled its dangerous road conditions warning as visibility has improved across the city.

"It has improved and there's a bit more of a haze around now," BOM duty forecaster Helen Reid told AAP on Saturday.

At least a dozen domestic flights and four international flights in and out of Sydney are still delayed.

Travellers are urged to check with airlines about their flight status.

Sunday morning isn't expected to be as foggy, but some patches are forecast in Sydney's west.