Police say they are investigating following a "suspicious" house fire in Pilliga over the weekend.

A police spokesperson said emergency services were called to Dangar Street at around 9:20pm on Saturday 8 November.

They said Rural Fire Service (RFS) and Fire and Rescue crews arrived to find the rental well alight.

The house was unoccupied at the time, but was completely destroyed.

The blaze has left the family of four homeless.

A witness told the Western Plains Appp that they were at a nearby property with family members when they smelled smoke.

"One of our family ran around the side and there were three people walking away from the house saying 'f**k them, they deserve what they get,'" the person said.

"Within 15 minutes, the fire was too far to be stopped."

The witness said that the three people they saw were a woman appearing in her mid-20s and two males roughly 18-years-old.

The home in Pilliga well alight. [IMAGE SUPPLIED]

They claim that the woman had thrown a flaming rag under a vehicle outside the house shortly before the house fire was noticed.

The rag was removed from under the vehicle before it caught fire.

"Officers attached to Oxley Police District established a crime scene and commenced investigations into the circumstances surrounding the blaze," a police spokesperson said.

"The fire is being treated as suspicious."