Private boat owners and surf lifesavers have joined efforts to rescue people stranded on beaches as bushfires swept Sydney's Royal National Park.
An emergency warning for the two out of control fires south of Sydney was downgraded to a watch and act alert on Saturday evening.
However a number of visitors stranded by fire had been rescued on beaches adjacent the national park, NSW Rural Fire Service said.
"There are a number of boats being utilised by surf lifesavers, NSW Police Force and some private citizens that are picking some people up from beaches in the area," RFS spokesman James Morris told AAP earlier in the evening.
Mr Morris said those caught up in the drama had found the park's many beaches to be the best places to take cover.
"They're providing the best protection given the fact a lot of the escape routes are through the middle of the bushland which isn't safe at the moment given the intensity of that fire."
More than 100 firefighters battled the blaze on Saturday evening, supported by water bombers and aircraft.
While 200 people were escorted from popular tourist spot Wattamola Beach to Bundeena by RFS crews, Mr Morris said a large number were still being observed on walking tracks by circling planes.
"There is still a significant number of people in there," he said.
Given the limited mobile coverage in the Royal National Park, Mr Morris said many people in the bushland were "unlikely" to have received emergency text warnings.
Embers are believed to have caused a second fire nearby on Sir Bertram Stevens Drive at Flat Rock.
Aircraft including Nancy Bird the DC10 have been busy today supporting firefighters on the ground, like here at Pilliga fire. Great machines providing great support. #nswrfs pic.twitter.com/e1I6vYUSl3— NSW RFS (@NSWRFS) January 20, 2018
All roads into the Royal National Park were closed and motorists advised to avoid the area, while people in southwestern Sydney and the Illawarra have been advised to be wary of smoke.
Further south, near Bowral, rural properties in the Alders and Crees Road areas in Bannaby may come under threat from a grassfire, the NSW Rural Fire Service says.
Shoutout to all those working behind the scenes helping to keep our firefighters well fed and watered today. Thanks also to the local supermarkets who have donated food. Pic: @Engadine_RFB #NSWRFS pic.twitter.com/Gi40aUBGxB— NSW RFS (@NSWRFS) January 20, 2018
The 634-hectare blaze is at watch-and-act alert level with firefighters and an aircraft on scene to try to slow its spread.
A watch and act alert has also been issued north of Tamworth, where there's an out of control 3500-hectare fire. The RFS is concerned isolated rural properties may be threatened 10km southwest of Bundarra.
Firefighters are conducting backburning operations in the area and the Newell Highway is shut between Narrabri and Coonabarabran and likely to remain closed on Saturday.