A serious early hours crash involving one car took place on the A970 at Fladdabister on Saturday night.
Two casualties were reported at the scene and were taken to hospital. The road is closed and a diversion is in place.
Scottish Fire and Rescue Service control room staff in Dundee told The Shetland Times the two people involved were both released from the wreckage prior to the arrival of fire units.
But crews from two appliances attending remained on the scene to assist police with lighting while investigations were carried out.
On Sunday morning the chairman of Shetland Islands Council’s environment and transport committee, Ryan Thomson, was advising motorists to use a short diversion in place using an old stretch of single track road which runs parallel to the main route.
He posted online: “Road closure will remain in place until further notice. Please go slowly on diversion route.”
Police Scotland said in a statement: “Police in Shetland are currently dealing with a serious road traffic collision on the A970 between the north Fladdabister Junction and Cunningsburgh.
“The road is currently closed to allow the Road Policing Unit to carry out their investigations and a diversion is in place via the single track road through Fladdabister.
“Motorists are requested to be mindful the diversion will be along a single track road and should allow extra time and patience for their travel.
“The collision happened shortly before midnight and Police Scotland are appealing for any
witnesses to come forward.”