Shark sighting closes Maroubra beach

A shark sighting emptied the water at Maroubra Beach in Sydney this morning in the latest shark-related incident on Australia's beaches.

Patricia Garvie raised the alarm after seeing a mysterious splash 100 metres out from the shore on the south end of the beach.

"It did look quite big," she said.

"I thought I saw someone swimming but it was a really big swim."

It was estimated the shark could be potentially four metres long.

The sighting triggered a full-scale search from air, water and shore.

The beach was closed for half an hour, but the shark could not be located.

Just last week, a 4.6-metre great white shark was found dead in nets at the same beach.

In the past few weeks, there have been multiple shark sightings from Bondi to Maroubra, with other sightings at Tamarama and Bronte.