Three teenage divers were left stranded on a reef for nearly an hour, surrounded by multiple sharks, before they were rescued.

The boys, two aged 16 and one 17-year-old were swimming at Cosy Corner beach south of Hamelin Bay around 2:00pm yesterday when they first spotted the sharks.

It is believed the sharks appeared after the boys speared a fish in the water. They then sought refuge on a nearby reef and called for help.

Sergeant David Wall said it was difficult to understand what the reporting person was saying because it was a broken message, then a second message came through that they had seen a shark.

"We assumed that it was something like the movie, The Shallows, and that they were stuck on the reef and surrounded by a shark," he said.

"So, while we were on route to Cosy Corner, I called in the sea rescue for assistance."

When police reached the beach they said they could see three people standing on the reef knee deep in water and signalled to them that help was on the way.

Shortly after the Westpac Rescue helicopter arrived at the scene and hovered over the divers, before directing them through a small channel onto another part of the reef to wait for the rescue boat.

Augusta Volunteer Marine Rescue vessel arrived about five minutes later, pulled up alongside the reef, collected the boys and conveyed them to shore.

The boys advised the police that there were five or six sharks circling them which they believed to be bronze whalers; the largest about three metres.

None of the divers received any injuries.

Minister for Water Dave Kelly said the boys were wearing personal shark deterrents during the incident.

Fisheries minister Dave Kelly said the teenagers were wearing personal shark deterrents. ( ABC News: Jacob Kagi )

"They were spearfishing, which is quite a hazardous activity," he said.

"They did the right thing by choosing to wear a personal shark deterrent, which I'm sure assisted them in that circumstance."

Augusta Police said all credit for the rescue went to the volunteers on the rescue boat and helicopter.

"It was the volunteers on the rescue boat that you take your hat off too, they stopped whatever they were doing in their private lives on a Saturday to answer the call for help to come and save someone."

Sergeant Wall said after his call, it took the volunteers around 40 minutes to launch the boat, drive it to the reef and rescue the three boys.

He also praised the teenagers for their quick reaction to the situation.

"These young fellas did the right thing, they knew that they were obviously outgunned by the sharks and made the smart decision to seek refuge," he said.

Sergeant Wall said despite no other reports of shark sightings in the area recently, people should remain cautious.

He advised anyone who found themselves in a similar situation to avoid panicking.