The Sans Souci Bathers Pavilion and the surrounding area has been closed to the public after investigations by Georges River Council found the building to be structurally unsound.
Last Thursday, Engineering firm Cardno assessed the structure of the old building and its foundations.
The assessment uncovered that the building is not stable and is not suitable for people, especially larger groups, to congregate around.
In the interests of public safety and the safety of local residents, Georges River Council has now fenced-off the area around the pavilion.
The fencing is to ensure members of the public remain safe until such a time as when further assessments can be made and the structural integrity of the building can be improved, a council spokesman said.
The council anticipates that the final structural assessment will be completed within the next 30 days and further updates will be provided at that time.
During this time, the council asks that members of the public note the Sans Souci Bathers Pavilion is not safe and to adhere to the warning signs around the area.
Last year the council decided to carry out restoration works of the heritage-listed pavilion prior to leasing it to a private operator.
The council was is expected to open tenders for a private contractor to carry out the restoration works of the vintage 1933 art deco-style pavilion at 4 Water Street, Sans Souci.
On completion of the restoration works, the council will call for expressions of interest to lease the pavilion for a term of 21 years.
The former Kogarah Council first called for tenders for redevelopment of the heritage-listed pavilion in 2004.
In 2011, Blakehurst Marina Pty Ltd applied to redevelop the bathers pavilion into a 120-seat family restaurant at a cost of $660,000.
The original DA was modified to remove the proposal for an outdoor eating area and kiosk.
Residents said the building was dilapidated and an eyesore which should either be restored or demolished.
At the time, nspections found while there was concrete cancer and exposed steel the building was structurally sound and could be retained.
Others said it should be retained for community use or as a regional museum and not leased to a private operator.
Last December the council noted that the Planning Minister had not granted consent for a proposed lease of the pavilion proposed in 2015.
