Guernsey's Public Health Team has advised that hospitality staff should be swabbed at venues the group attended.
It's understood surge testing is being carried out in Sark following at least seven visitors testing positive for Covid-19 after they had left the island.
Sark's government's Pandemic Emergency Committee issued a notice advising of the cases.
"These visitors did attend several local establishments which have been informed, and the Medical Centre are contacting these premises to obtain surveillance swabs."
Surge testing is being used to pick up any other possible Covid cases and prevent the virus spreading.
Anyone in Sark who is experiencing coronavirus symptoms should contact the Medical Centre to arrange a test.
More to follow...

85 home planned for Forest site in Guernsey
Sewage outfall failure on Guernsey's east coast
Guernsey's airline sets up Southampton base
Cuts to services in Guernsey considered under tax review
Solar panels mandatory on new Guernsey homes
Average rent in Guernsey up 45% over five years
Grow goes to Chelsea Flower Show
Mariners reminded to respect Alderney’s Puffin Friendly Zone