UPDATE: A LARGE bushfire at Coonabarabran that destroyed 53 homes in NSW has been contained.

Around 90 firefighters are working to keep the blaze under control.

The RFS says crews will continue mopping up and patrolling the area at Bugaldie, eight kilometres west of Coonabarabran, where 113 outbuildings, livestock and farm machinery as well as 53,000ha of land have been destroyed.

A fire believed to have been started lightning on Friday night is also continuing to burn behind containment lines in the Ku-ring-gai National Park north of Sydney.

The RFS says walking access to The Basin, in Pittwater, is restricted and smoke can be seen as far as the Central Coast.

Firefighting operations have been scaled down as firefighters, helped by milder weather conditions, gain the upper hand.

More than 100 fires are still active but the fire danger has been downgraded to low to moderate across the state.