Blue Mountains bushfire continues to burn overnight as residents remain vigilant

Waterbombing helicopters have helped more than 100 firefighters battle an out-of-control bushfire in NSW's Blue Mountains, which will be monitored overnight.

The NSW Rural Fire Service earlier issued a watch and act alert for residents in Wentworth Falls after the fire broke out this morning, but have since downgraded it to advice. 

Residents should check with the Rural Fire Service or call 1800 679 737 for updates. 

Locals are urged to stay vigilant and to follow the advice of firefighters on the ground. 

The fire is burning between the clifftop and Little Switzerland Drive, near the intersection of Hordern Road and to the west of Tableland Road.

The peak wind gusts of up to 70km/h were not reached, which aided firefighting efforts. Winds are expected to ease even further this evening.

A telephone emergency alert has been issued to residents in the area.

Firefighters have completed work to contain the blaze and will monitor it overnight and return tomorrow to contain it further.

Fire fighting efforts were hampered after another fire was deliberately lit near the town of Blaxland, at the base of the mountains.

Fire crews were able to bring the blaze under control, and a man was arrested nearby.