Lifeguards are considering closing part of Sumner Beach, after two incidents requiring a rescue helicopter within a matter of hours.
Two people in their 20s are in hospital after being caught in a rip near Shag Point.
Police and a rescue helicopter were deployed, but the two had already been rescued from the water at around 2pm.
The rescue helicopter was alerted 10 minutes later to four people caught in a rip, but the group were again safely ashore by the time the chopper arrived.
Friends of two of the men who were rescued said a group of teenagers saved one, and a surfer rescued the other, Fairfax reported.
The two men were reportedly colleagues and were going for a pre-work swim.
A police spokesperson said a life boat and a jetski headed out to assist the swimmers.
She said two people were out of the water by 2pm, and were taken to hospital in a moderate condition.
Garden City Rescue Helicopter pilot Rick Knight said all the swimmers caught in the rip were now safe.
The rescue helicopter was called to help two swimmers but by the time they got there they had been helped out of the water by other swimmers.
Knight said the pair had swallowed some water and were taken to hospital for medical attention.
Soon after, the helicopter was called to help another four people stuck in a rip but before they could get there, the crew were told all four were safely ashore.
Knight warned there were large swells at the bar and swimmers should take care.