Wollongong City Council is working with the Illawarra Historical Society to create a register of more than 45 headstones damaged by vandals at Wollongong Cemetery last week.

The council says the process could take a long time as many of the headstones date back from the mid 1800s.

The council's property and recreation manager, Peter Coyte, says monuments in cemeteries are not usually council assets.

But Mr Coyte says given the historical significance of the gravestones, the council will assist in some repairs.

Families with queries about their ancestors' graves are urged to contact the council on 4227 7780.