The Hjaltland will now depart Lerwick at 3.30pm, with arrivals into Kirkwall and Aberdeen subject to minor delays. The northbound ferry is unaffected.
The Lerwick-Aberdeen freight sailing is now departing at 9pm instead of 6pm, while the northbound trip may be delayed.
Flights from Sumburgh Airport have also been disrupted, with the morning trips to Aberdeen and Edinburgh both cancelled.
The 8.55am arrival from Edinburgh was also called off.
Shetland Islands Council staff have also warned that the Yell Sound ferry is likely to drop to a single-vessel service after around 11am as winds pick up.
Inter-island flight operator Airtask said at 10.30am that its flights were on hold and while the weather will be monitored, it is unlikely services will run.