More than 40 firefighters from across Lancashire are battling the blaze which burst into flames again at around 8.30am on Tuesday.
Initially seven fire crews were in attendance including Bamber Bridge, Darwen, Leyland, Rawtenstall’s soft track and wildfire unit and crews from Greater Manchester along with the fire service drone.
At around 10pm most of the crews were sent back to their stations, with one fire engine remaining at the scene to monitor the fire and damp down hot spots.
Nobody has been injured and no property has been damaged by the fire, although there may be environmental consequences, fire fighters warn.
Crews are now working to extinguish the blaze using beaters to swat the fire out.
A spokesman for the fire service said: "We came off the moor when light faded because it is extremely hazardous to work on moorland fires in the dark.
This morning, the fire flared up again. Crews, mostly from East Lancashire, are now actively working to extinguish the fire.
"Seven fire engines are in attendance, but the engines are largely being used as personnel carriers to get enough firefighters up to the scene.
"They're using misting sprays and beaters to swat out the fire.
"We do not currently know what started the fire."
Firefighters are now warning members of the public to take care when travelling around large areas of moorland which are particularly vulnerable to widespread damage caused by fires.
A spokesman said: "When you're out and about in the dry weather on stretches of grassland and fells, please take care.
"Don't throw your discarded cigarettes out of car windows or start camp fires on the moors.
"Fires which start on moors can spread quickly in these conditions and the consequences can be serious."
In the last three years, fire crews in Lancashire have attended 82 incidents involving wildfires.