Beecroft weapons range and peninsula is closed, in response to health concerns about the spread of COVID-19.
The closure was announced online on March 27.
"In the interest of staff and visitor safety and in line with Government advice, it has been decided that BWR will remain closed to all public access until May 31," the post read.
"The closure will be reviewed mid-May or as updates to government advice are issued.
"We apologise for any inconvenience, however the safety of staff and visitors remain our highest priority."
The area is a popular hiking and camping spot.