Second officer at Cork City Fire Brigade, Victor Shine, expects the number of people squatting in unoccupied and derelict buildings will increase significantly in the winter.
Campaigners Frank O’Connor and Jude Sherry say they have identified 700 derelict properties within a 2km radius of the city centre.
Mr Shine said some people are bypassing electrical systems to tap into power supplies.
“The power may have been disconnected and people are illegally tapping into the supply,” he said.
“Obviously, this is extremely dangerous. There are also people lighting fires inside properties, using any materials available to them. Sometimes that’s furniture, other times it’s building materials. They are even tearing down doors to use as fuel for a fire. Now that we are coming into winter, this kind of activity is going to be on the increase.