As the State braces to face its worst bushfire danger in history, the Rural Fire Service fears an arsonist is at work in the Hunter Valley.
The RFS says it has responded to a fire almost every day for the past week in the Howes Valley area, south-west of Singleton.
One of those fires is still burning and is currently being monitored by the National Parks and Wildlife Service.
Hunter Valley Fire Superintendent Paul Jones says it is worrying.
"We've had six suspicious fires in the Howes Valley area," he said.
"We suspect they're all deliberately lit.
"They're still under investigation by RFS fire investigators and police, but the location and the type of fires, they're very suspicious.
"We believe someone may be foolishly deliberately lighting fires down that area."
Superintendent Jones is urging the community to keep an eye out for suspicious activity.
"We'll be providing a report to police, and they're conducting their own inquires as well," he said.
"If people can be mindful and keep an eye out for any suspicious behaviour and report that to the police, that would be also very useful."
Today is the worst fire danger day in the State's history, with water bombing aircraft on standby at Scone to cover the region in the event of a break-out.
© ABC 2013
12:38 EST Tropical Cyclone Jack has rapidly developed over the warm waters of the Indian Ocean in the past 24 hours, making it the 10th system to be named this season.