Police on the mid north coast say they are dismayed by an incident on the weekend where a young boy is believed to have deliberately lit a bushfire.

The Rural Fire Service (RFS) was called to a fire in West Kempsey which was burning across about 30 metres of bushland.

Police spokeswoman Catherine Poczynski said an investigation was launched which led detectives to a 10-year old boy.

"At about 6:00 pm (ADST) on Saturday October 26, police were called to bushland behind Dunghutti Place, Greenhill after the Rural Fire Service extinguished a bushfire at the location," she said.

"They then interviewed the 10-year old boy as it was believed to have been a deliberately lit bushfire."

Ms Poczynski said the boy who was interviewed later on Saturday night was in the presence of a family member.

"He was released pending further investigations," she said.

"But police are continuing their inquiries and they are appealing for anyone with information to contact Crime Stoppers."