A temporary fence has been put up to prevent people visiting Splash Point in Seaford after storms left the beauty spot in a dangerous state.
Lewes District Council said part of the path had fallen away and the wall underneath had been undermined.
The cliffs are home to a colony of hundreds of kittiwakes, which are a tourist attraction for the town.
A spokesperson for district council said: “The pathway and sea wall at the extreme end of Seaford Promenade at Splash Point has been badly damaged in the storms, particularly those of 14 February.
“Part of the path has fallen away and the wall beneath has been undermined.
“The area is dangerous and, following an alert from Seaford Town Council, we have temporarily closed it on safety grounds.
“We put up temporary fencing at the beginning of last week and something more substantial at the end of the week.
“Our primary concern is for public safety so we will continue to monitor the situation and liaise with Seaford Town Council and the Crown Estates Commissioners over what can be done about it.”
The district council said it did not know when it could be repaired at this stage.
The RSPB said it stopped running kittiwake observation events at Splash Point in 2012 because of access problems and declining visitors.
Seaford district and town councillor Sam Adeniji, whose ward includes Splash Point, said he would do his utmost to ensure it was repaired and reopened as soon as possible.
Residents were expressing concerns on social media about putting up the fence against a backdrop of natural beauty and said Newhaven Beach sprang to mind.
Cllr Adeniji said: “Splash Point is a vital tourist attraction and the kittiwakes are spectacular.
“I have had initial assurances that this will be repaired as soon as the weather improves.
“Nonetheless I am not giving up and will continue to apply pressure until the district council publicly acknowledges the need for a speedy repair, tell us when and by whom the works will be done.”