Can E-tagging sharks could help prevent shark attacks?

The NSW government is turning to a new high-tech approach to shark tracking in the wake of three recent attacks off Sydney beaches.

The government's initiatives, to be released for public comment by the end of the month, include a DNA library, GPS monitoring of nets and an electronic tagging program.

It comes after the third shark attack in Sydney in three weeks, in which 15-year-old Andrew Lindop was mauled while surfing off Avalon Beach on Sunday by what was believed to be a two metre-long great white.

The teenager remains in a satisfactory condition in a Sydney hospital, after suffering deep cuts to left thigh that required four hours of surgery.

Andrew's sister on Monday said he was making jokes, and was being "really, really brave".

The NSW opposition has criticised the government for not doing enough to prevent shark attacks.

"We have a situation that shark nets are deteriorating, the minister has not renewed the quota on catching sharks, and the time of the Westpac (helicopter) shark patrol has been cut," opposition industry spokesman Duncan Gay said on Monday.

But Primary Industries Minister Ian Macdonald said the government will adopt a range of new scientifically-based measures as part of its review of the NSW Shark Meshing (Bather Protection) Program.

It is the first public review of the program since 1972.

"The recent series of shark attacks in the Sydney area has caused community concern and it should be known the government is taking action," Mr Macdonald said in a statement.

He said the measures would include a DNA library, a new tagging program and research on population trend, patterns and movements, to help identify high risk periods and hot spots.

Mr Macdonald said he would be meeting with lifesaver groups later in the week to discuss practical options that could be implemented.

He rejected calls for aerial patrols over beaches, saying a 2006 summit found fixed wing aircraft could not cover enough area to be effective.

"This is for a number of reasons - identification of species (even telling whether things are sharks or just a big fish) is difficult from a plane," he said.

"In bad light - when sharks are particularly active - and at dawn and dusk (when all three recent attacks in the Sydney area occurred), visibility is poor from a plane."

The attack off Avalon Beach was the third shark attack in as many weeks.

Navy clearance diver Paul de Gelder lost a hand and a leg and was lucky to survive after being mauled by a 2.7-metre bull shark in Sydney Harbour on February 11.

Just a day later, 33-year-old surfer Glenn Orgias was attacked at Bondi Beach by a 2.5-metre great white that shook him and nearly severed his left hand.