A fifteen-foot great white shark has been found dead in a net off Maroubra beach, one of Sydney’s most popular surf spots.

State authorities confirmed the shark was found dead in the nets after a fisherman posted images of it being removed. The beach was closed until about 11am.

“[The New South Wales Department of Primary Industries] can confirm a 4.65 metre White Shark was removed from the Maroubra shark meshing net this morning by contractors during a routine check,” a spokesperson said.

“DPI shark scientists have completed a full necropsy on the White shark.”

Adam Cree, from Blue Reef Fishing Charters, who saw the shark being removed, said it was “the biggest shark I’ve ever seen”.

”And I’ve been running charters off Sydney for 20 years,” he told ABC News. 

“We catch small sharks on a regular basis but not to that scale. That was definitely a man-eater, no question about it."

Jason Moyce, the fisherman, said on Facebook that the shark was “pushing over a ton in weight”. 

Referring to the controversy over shark nets – which critics say harm marine life without necessarily making beaches safer – he noted that he had not caught the shark and urged people not to “abuse” the officials who removed it. 

“I do know the guys who do this job and they work hard to keep our beaches safe – whether you agree with shark net protection or not, these guys are not the ones to abuse.”

Following a spate of shark attacks and sightings in recent years, authorities have adopted a range of measures to improve safety.

This includes aerial and drone surveillance and using special hooks which are connected to buoys and can tag sharks and allow them to be tracked. Nets have been used in NSW since the 1930s but regularly prompt debate over whether they should be removed or extended.

The government said its beach nets do not create an enclosed area  or provide a barrier between swimmers and sharks. 

Joseph Smith, a fellow diver, said he saw a "pool of blood" near their boat.

"He’d speared a mackerel and then they took the mackerel off his spear rod … then the sharks turned on him,” he told ABC News.

"He said he saw about seven [sharks], but it was that quick that he didn’t see the shark who bit him."