Days of wild weather on Sydney's coastline following months of bad conditions have severely eroded metres of major beaches.
But it could get worse as strong weather continues and another possible La Niña event looms later in the year.
On Monday night, a lifeguard hut at North Cronulla was moved after erosion ate away at the sand beneath it.
University of NSW coastal researcher Mitchell Harley said erosion had claimed about 30 metres of beach in some areas.
"It's been an extreme couple of years really, since 2020," Dr Harley said.
"We've had these back-to-back La Niñas, [we're] maybe looking at a third, and with that, we've seen huge impacts to Sydney's beaches.
Dangerous scarps have formed at some beaches, and in North Cronulla some access ways remain closed.
Local engineer Ian MacDonald said it was the most coastal erosion he had seen in 60 years.
"Rocks are exposed that have never been exposed before," he said.
"The entire beach — Wanda, Elouera, North Cronulla, Cronulla — the sand has been removed by at least three or four metres.
"If this continues, it worries me that where I'm standing now will be in the water."
A spokesperson for Sutherland Shire Council said extensive works were being done to address the erosion.
"Council continues to assess the damage caused to the North Cronulla sea wall, and a plan of works is being developed to undertake urgent reinforcement of the sea wall which are expected to commence within days," they said.
Dr Harley said strong waves were expected to continue in coming days and, combined with possible winter storms, infrastructure at some beaches would be under threat.
"Anything that's built too close to the coast and is inside the zone where the beach naturally likes to fluctuate is a concern," he said.
"At the moment, we're at the extreme end of that fluctuation cycle … there's a big concern for that being undermined and potentially falling into the ocean.
"The beaches are sitting ducks if we see further erosion."
