About 200 in-lamb merino ewes worth as much as $50,000 have been stolen from a station in Omarama.
The sheep went missing from a remote part of the Ribbonwood Station between the end of August and 26 September.
Constable Nayland Smith says the thefts were well organised and several people were probably involved.
He says the incident may be linked to others in the area, including one in Cromwell where 190 sheep went missing.
Federated Farmers says it is the biggest incident of sheep stealing since the theft of 300 sheep from a station in Mid-Canterbury three years ago.
Meat and Fibre chairperson Jeanette Maxwell says incidents of sheep rustling tend to spike when prices for stock are high.
