Commuters in Sydney are being warned of delays this morning after heavy fog caused the cancellation of ferry services.

Transport authorities have told passengers to make alternative travel arrangements or consider catching a bus instead.

There is no forecast for a resumption of ferry services.

Passengers have been told to expect longer travel times, to listen for service announcements and to check information boards for any updates.

There is no impact on flight services out of Sydney Airport.

The morning fog has settled on Sydney Harbour and has stretched into the city’s north and west. The fog is so thick this morning, the Sydney Harbour Bridge was barely visible from Milsons Point.

The fog is expected to clear later today, with temperatures in Sydney expected to reach a maximum of 21 degrees.

The Bureau of Meteorology has warned of large and powerful surf conditions in Sydney as winds pick up, making activities such as rock fishing, swimming and surfing a hazard.