The Department of Biodiversity, Conservation and Attractions (DBCA) say they are "sick and tired" of people illegally accessing the Port Kennedy Scientific Park and are calling on locals to dob them in.
The DBCA issued 40 infringements in 2025 for people accessing the reserve illegally by vehicle or dirt bike and estimate about $40,000 is spent annually on repairing fences and installing deterrents such as limestone boulders.
DBCA park manager Tim Fisher said dunes, wetlands and bird habits are being damaged in the A-class reserve.
"It's a shame to see the park getting wrecked like this, it's a beautiful reserve," he said.
"It's come to a point where we are sick and tired of the illegal access and damage being caused by some elements of the community."

Mr Fisher said they are fed up.
"The locals are really sick of it...we're doing everything we can to stop this but it's a huge task for our staff," he said.
"They destroy vegetation, they introduce disease and weeds.
"This is an A-class nature reserve, it's purpose here is to preserve fauna and flora."
Some locals are proposing a designated 4WD track to Long Point Beach.

The site of an illegal camp where a fire started last year. PIC: DBCA
The DBCA is asking people to report any illegal activity to the Regional Parks Unit on 9442 0300 or Crime Stoppers on 1800 333 000.
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