Port Stephens Lifeguard Service supervisor Phil Rock said a NSW Department of Primary Industries helicopter sighted a shark estimated to be between 2.5 and 2.6 metres long off the popular beach.

“We closed the beach down and pulled the people in the water out,” Mr Rock said.

After a sweep of the area, and confident the shark was gone, the beach was re-opened.

Later, the NSW DPI aerial team reported seeing a white shark in Shoal Bay, about 12.25pm.

The Shoal Bay shark was reported as being about 2.4m in length.

There was reportedly no swimmers in the water at the time of the sighting.

Aerial surveillance of Port Stephens only began in April this year.

It comes as part of the NSW Government’s shark management strategy, which was announced in October 2015.

A NSW DPI spokesman said the department contracts aerial surveillance companies to complete surveys over coastline areas.

An observer is also on board.

The aerial team that spotted the shark in Port Stephens on Thursday covers the coastline from Birubi Beach to Crowdy Head.

A flyover of the Briubi to Crowdy Head coastline will be carried out once a day, every day of the school holidays between April 30, 2016 and April 25, 2017, weather permitting.

“Authorities are alerted following a sighting of a shark if it is deemed to pose a risk to beachgoers,” the NSW DPI spokesman said.