The Herald published yesterday a picture of a NSW Government contractor hauling a 2.7-metre white pointer from the ocean, after it drowned in a net.

White pointers are listed as a vulnerable species and are protected in Australian waters.

Greens MP Ian Cohen said the nets were a 1930s method of dealing with sharks.

"Netting has been proven to be pretty ineffectual, from my perspective," Mr Cohen said.

"About 30 per cent of sharks caught up in the nets are on the inside coming out and the vast majority of creatures caught in the nets are harmless to humans."

The shark caught at Nobbys on Wednesday was believed to have been caught on the outside of a net.

The nets do not cover entire beaches and marine creatures can swim over, under and around them.

But marine experts said dolphins, seals, dugongs, whales, turtles and harmless sharks had been killed in the nets.

A Department of Primary Industries report said that the nets had been "effective in greatly reducing" the number of fatal shark attacks.

"Since the NSW shark meshing program was put in place in 1937, there has only been one fatal attack on a meshed beach," the report said.

"Before the program was in place, there was an average of one fatal shark attack every year in NSW waters."

Asked for details on the number of sharks caught in nets off Newcastle, a spokeswoman for Primary Industries Minister Ian Macdonald said his department was "finalising this data, which will be issued publicly as part of a report on the NSW shark meshing program".

Nobbys Beach nippers' co-ordinator Michael Mulligan said he was "not a strong believer" in the nets.

"They do help prevent sharks, but they don't run all the way up and down the coast," Mr Mulligan said.

"The sharks are either on one side of the net or the other.

"If they are caught on the shore side, how do they get back out and do they look for a food source on the shore side?"

Sharks that become entangled in the nets drown because they must swim to get oxygen and others creatures like whales and turtles die because they need to breathe air, experts say.

The department report said the nets were fitted with sonar devices and alarms to deter air-breathing creatures such as dolphins and whales.

Sydney Aquarium marine expert Amy Wilkes said the nets were harmful and the sonar devices and alarms "work for some marine life, but not others".