The stony beach is considered dangerous and signs are in place warning people not to swim.
Witness Glen Collins, on holiday from Australia, said he did not see how the four people came to be in the water.
He said at first he didn’t register what was happening, but quickly realised it was an emergency.
He said the man, boy, aged about 3 or 4, and younger woman were the first to emerge from the rough waters, the latter of whom had been “violently cartwheeled” in the surf.
The small dog also managed to scurry back onto land.
However, an older woman, aged about 50 to 60, remained stuck in the surf, he said.
He said a bystander and “absolute legend” had been helping and risked his life to try and get to her, but the wild surf knocked him around.
Another bystander was on the phone to emergency services.
The witness said he considered going in himself, but knew he couldn’t get to her even if he tried.
He said it was the most helpless he’d ever felt.
“We just watched this poor lady try with all her might.
“She would go under and we couldn’t see where she would resurface.”
Fortunately, the current eventually brought her close enough to shore that the young hero and the man, who had previously been in the water, were able to pull her ashore.
He said the injured woman was breathing but was exhausted and cold, and they lay jackets on her to try and warm her as emergency services arrived.
He said it was a horrible ordeal, but could have been much worse.
“I know for certain the young man deserves a commendation; he risked his life.”
He said it appeared the four people caught in the ordeal were a family.
A St John ambulance spokesman said they responded to the incident with two ambulances and a rapid response vehicle.
Four patients were assessed at the scene by ambulance crews.
Two of those patients were taken to hospital, one in a critical condition and one in a moderate condition.
Police also attended after receiving a report that “multiple people” had been pulled from the water.
The last fatalities in the water off Marine Parade happened in February 2020 and December 2021, when two young children drowned. The latter incident led to a dozen signs being erected along the foreshore warning people not to swim.
