A plane has reportedly crashed in Budawang National Park, about 35 kilometres west of Ulladulla.
NSW police said its officers were yet to reach the scene and were navigating "inaccessible" bushland.
A coordinated search was under way to look for the aircraft and confirm details of the reported incident, the police spokesman said.
A NSW Rural Fire Service spokesman said the service had dispatched a truck about 5.20pm in response to the call-out.
The police spokesman said the search area was spread across multiple police districts, and a number of emergency services may be assisting police.
It's understood the Australian Maritime Safety Authority has handed the search operations to NSW Police.
More to come
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