tiger shark

Spotted: Swimmers left the water. Photo: iStock

Harry Mitchell can list more than a dozen reasons why he disagrees with a state government report that branded his line of work costly and inefficient when it comes to protecting beachgoers from sharks.

''It contradicts what is actually happening out there, the weekend just gone,'' said the general manager of the Bendigo Bank Aerial Patrol in the Illawarra.

Mr Mitchell said the patrol's planes spotted about 14 sharks between 50 metres and 100 metres off unpatrolled Jervis Bay beaches ''at which people were having a pleasant day'' on Saturday.

The sightings, which forced swimmers from the water, followed an earlier pass over Port Kembla Beach, he said, where the patrol found two hammerhead sharks.

Mr Mitchell's south coast patrols were not part of a Department of Primary Industries helicopter trial, which began again this year on December 21. That coincided with the release of the department's report on last season's trial, which only spotted one shark per 100 kilometres flown between December last year and January this year.

The report questioned the effectiveness of aerial surveys - highlighting one instance where the trial failed to find a shark that took a bite at a surfer's board at Dee Why last December to underscore its ''serious concerns'' about their use as an early warning system.

Touchdown Helicopters in the Illawarra, which was contracted to carry out this year's trial, was unavailable for comment, a spokeswoman for the department said.

But Mr Mitchell, who counted flights among measures working to protect swimmers, was critical of the trial's methodology and cost.

These twice-daily flights on 47 days are part of the $200,000 the government has committed each year to initiatives within its aerial observation program.

Mr Mitchell said his company patrolled for six months of the year, funded by $500,000 in sponsorship, donations and contributions from local councils.

''I'm the first to admit that there's probably sharks that we don't see,'' Mr Mitchell said. ''But we see other things as well that can attract sharks like large schools of fish.''

Brent Manieri, a lifesaving officer at Surf Life Saving NSW, said the flights were an ''additional asset'' that fed information back to beach patrols.