29/03/2017 1:08 PM AEDT | Updated 29/03/2017 4:00 PM AEDT

Even Australia's Swimming Pools Aren't Safe From Sharks

'Everybody who swam in the pool this morning didn’t know… except one person.'

Local swimmers at an ocean pool on Sydney's northern beaches were unknowingly accompanied by a shark as they swam their laps on Tuesday morning.

It wasn't until a bystander pointed out the juvenile dusky whaler that they realised they weren't alone in the Palm Beach rock pool, with Jennifer Hill telling The Manly Daily she was relatively unfazed.

"It was a beautiful experience," she said.

"My initial response was obviously it wasn't very hungry because it had ample opportunity.

"Everybody who swam in the pool this morning didn't know...except one person."

It is believed that the shark had been washed into the pool overnight with the tide and was retrieved by a team of marine biologists who carried it to the nearby open water.