AERIAL beach patrols detect as few as one in eight sharks and give the public ''an inflated sense of protection against shark attack'', a damning state government report says.

The findings cast doubt on whether shark patrols protect bathers from harm, and call into question the millions of dollars in government funding, sponsorship and donations poured into patrols across Australia each year.

The world-first study by the NSW Department of Primary Industries was based on a trial at Jervis Bay on the south coast, using artificial sharks placed at various depths.

Pilot Chad Carey from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa today.

On the lookout … Chad Carey, of Australian Aerial Patrol, searches for sharks between Helensburgh and Gerroa on Friday. Photo: Adam McLean

It found plane crews spotted just 12.5 per cent of the dummies, and helicopters - the main form of government-funded patrols in NSW - detected 17.1 per cent.

The findings, released last year, concluded that more experienced crew were not necessarily better shark spotters, and that observers missed high numbers of the artificial sharks, even at ''shallower depths than those at which potentially dangerous sharks inhabit''.

''This is a clear concern when the purpose of these patrols is to provide a warning of shark presence to the beachgoing public,'' the report said.

Pilot Chad Carey from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa. Click for more photos

Aerial shark patrol

Pilot Chad Carey from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa. Photo: Adam McLean

  • Pilot Chad Carey from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa.
  • Observer Bob Chapman from the Australian Aerial Patrol cleaning the air craft after a patrol over the coastline from Helensburgh and Gerroa.
  • Observer Bob Chapman from the Australian Aerial Patrol cleaning the air craft after a patrol over the coastline from Helensburgh and Gerroa.
  • Pilot Chad Carey from the Australian Aerial Patrol before a patrol over the coastline from Helensburgh and Gerroa.
  • Observer Bob Chapman left and  flight co-ordinator Rob Newell right from the Australian Aerial Patrol cleaning the air craft after a patrol over the coastline from Helensburgh and Gerroa.
  • Pilot Chad Carey from the Illawarra Aerial Patrol before a patrol over the coastline from Helensburgh and Gerroa.
  • Pilot Chad Carey from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa.
  • Observer Bob Chapman from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa.
  • Kiama Beach from the Australian Aerial Patrol plane during a patrol over the coastline from Helensburgh and Gerroa.
  • Co ordinator Rob Newell flight from the Illawarra Aerial Patrol during a patrol over the coastline from Helensburgh and Gerroa.

Several shark attacks and sightings have occurred off the NSW coast this summer, including an attack off Dee Why last Sunday, when a great white bit a chunk from the surfboard of an off-duty lifeguard. He was not injured.

The government has enlisted Newcastle Helicopters to conduct aerial shark patrols this summer from Seal Rocks, on the mid-north coast, to the south of the Illawarra. It would not comment on the report.

Its contract finishes at the end of this month, and the Minister for Primary Industries, Katrina Hodgkinson, did not say whether funding would be renewed.

A department spokesman would not disclose how much the contract was worth but said the Coalition committed $200,000 a year to aerial shark surveillance and shark safety research before the 2011 election. He said the patrols, which have taken place every summer since 2009, were still in the trial stage and were designed to ''provide a full scientific evaluation of aerial surveillance as a bather protection measure''.

The Illawarra-based Australian Aerial Patrol, whose planes took part in the shark sighting study, relies on public donations and sponsorship, including a deal with Bendigo Bank, to meet its $800,000 annual running costs.

A pilot, Barry Sandry, insisted aerial shark patrols were a valuable early warning system. ''We've been operating for 57 years … We know the [shark] activity that is out there on a daily basis. If the service wasn't effective we wouldn't continue to do it.''

The service also conducted searches and bushfire patrols, Mr Sandry said.

The report recommended bolstering funding for lifeguard-run shark surveillance on beaches and improving public knowledge of shark risks.

The government has recently offered grants for observation towers and expanded the SharkSmart awareness program online, the department spokesman said.