State forests in the Hunter and elsewhere across NSW will be closed for the Christmas and New Year period, meaning camping and other activities will be off limits.
The decision was taken due to bushfire risk and expected heatwaves, Forestry Corporation of NSW tourism manager Louise Faulkner said.
She added that some areas were "already being fire-affected".
The closures mean picnic and camping areas, walking tracks and lookouts will be out of bounds.
Police will patrol visitor areas in the forests to alert people they are closed due to fire risk.
"It's not about enforcement, it's about making sure everybody knows," she said.
In the Hunter, forests at Chichester, Barrington Tops and the Watagan mountains will be closed, meaning numerous free camping areas - where many people usually stay over the holidays - will be shut down.
"Chichester State Forest in the Upper Hunter is closed, including both the Allyn River and Telegherry River visitor areas," Ms Faulkner said.
The closures in the Barrington Tops and Chichester forests include camping and day-trip areas such as Manning River, Ladies Well, Currawong, Frying Pan, Telegherry, Allyn River, White Rock and Mount Allyn.
Closures in the Watagans forests cover the Pines picnic and camping areas; Heaton, Hunter and McLean lookouts; The Basin and Olney HQ.
"Even though we all know there's a fire situation, people might not necessarily know their favourite or beloved regular annual forest spot for Christmas is closed," Ms Faulkner said.
Forestry staff have been working on firefighting since August.
"The majority of our staff remain on deployment to fire grounds, firefighting and incident management or control centres, alongside the RFS and other agencies. As a result, our staff resources are stretched," she said.
She said the forest closures were about safety.
"If a situation emerges and fire happens very quickly, given that a lot of our staff are fighting fires in other areas, it may be very hard to have the type of response we normally would to help evacuate visitors," she said.
"We want to make sure that people aren't in places that are hard to get out of if something happened."
She said picnics and camping in state forests were, for many, annual Christmas-New Year family gatherings.
"However, this year, the ongoing fire risk means it simply isn't safe."
NSW national parks haven't been subject to the same kind of blanket closure.
A National Parks and Wildlife spokesperson said the decision to close a national park was "not taken lightly, as the safety of park visitors is paramount".
"While a number of parks in NSW remain open, these can be quickly closed at short notice in forecast dangerous weather conditions," the spokesperson said.
"For specific parks that are closed, check our alerts page."
