A woman living nearby said there were three dairy farms in the area of the incident, all with silos.
An Otago Regional Rescue Helicopter has been dispatched from Dunedin after reports of a man trapped in a silo in South Otago.
A police spokeswoman confirmed the man had fallen into a Silo in the Hillend Area, near the intersection of HIllend and Coe Rds, north of Balclutha.
WorkSafe has been advised and police, fire and St John ambulance are all involved.
The helicopter left Taieri airfield about 11.50am and would be arriving on scene shortly.