The Mayor said the demolition was to help prevent future flooding and destruction around the Odaw river.
“No more shall we allow a disaster of such nature to visit the city of Accra,” he told the residents.
Mr Vanderpuije explained one of the reasons for the June 3 disaster was that water cannot flow from the Odaw river partly due to the activities of the residents at Old Fadama hence the Accra Metropolitan Assembly (MA) has to demolish those structures.
Hundreds of structures at Old Fadama, were demolished on Saturday June 20 by a task force of the AMA, rendering scores of people homeless.
Mr Vanderpuije told journalists that one of the objectives of the exercise was to expand the natural borders of the Korle Lagoon, to allow it to flow.
He said the dwellers had built structures along the banks of the lagoon and filled it with sawdust, thereby hindering the flow of water.