A group of travellers has set-up camp at the site of the Derby Fireplace Company.
According to police, four caravans and eight vehicles are at the site, and the owner of the land has locked the gate to stop people entering or leaving.
Police were called at 11.40am to Wyvern Way after the travellers arrived.
A spokesman for the force said the owner was concerned because the land was used for car-parking for Derby County fans at home matches.
