The dangerous buildings section of South Dublin County Council is investigating reports of unsafe balconies in Tallaght.
Some owners of apartments in Hunterswood in Ballycullen have been warned not to step on their terraces until further notice.
It is after engineers flagged those who have wooden-supported balconies instead of steel are rotting at a faster rate than first thought.
Fianna Fáil Councillor Charlie O'Connor says the local authority is now on the case.
He said: "We made immediate contact with South Dublin County Council this morning and brought the story to the direct attention of senior management.
"They have told us and assured us that they are investigating the situation and have specifically asked their dangerous buildings section to investigate."