Australians are being warned to stay alert on beaches after numerous sharks were spotted hunting unusually close to shore in New South Wales.

New South Wales Department of Primary Industries (NSWDPI) advised on social media that "a large number of white, bull and whaler sharks" were spotted by using aerial surveillance near the coastal towns of Forster and Tuncurry.

Footage showed the sharks feeding on bait fish along with a Bryde's whale close to the shore. According to one NSWDPI shark scientist speaking to, local fishers said the activity usually took place further offshore, making the sighting surprisingly close to beaches.

NSWDPI put out alerts about the large number of sharks in the area and people were cautioned to be sensible in the water.

A week beforehand, the department announced that helicopters and drones would be deployed to keep an eye out around beaches as school holidays got underway and families started taking beach trips.

Sarah Fairfull, NSWDPI acting deputy director general fisheries, said: "Sharks are a natural part of our environment, however a better awareness and understanding of sharks and their behaviour can help everyone enjoy the beach and reduce their risk of a shark encounter these school holidays."

Fairfull added that the drones would be fitted with a siren to alarm those in the water if a shark is spotted. Other safety measures include the Sharksmart App and Twitter account, which alert people when a tagged shark is close to shore.

"This round of drone surveillance complements our other measures under the $16m [£9.4m] Shark Management Strategy." Fairfull said.

Australia shark shoreline
A shark spotted off the coast of Australia