A fire that significantly damaged a unit at Muswellbrook on Tuesday night is being treated as suspicious.
A 41-year-old woman was assessed for smoke inhalation after emergency services were called to the Tindale Street unit about 7.45pm. Police said she declined hospital treatment, and no one was injured in the blaze.
The unit was significantly damaged but no other homes were affected as three Fire and Rescue NSW crews managed to extinguish the flames.
Hunter Valley police established a crime scene, which was held overnight. A Fire and Rescue dog was deployed to the scene on Wednesday to determine whether or not an accelerant was used.
An investigation is underway into the circumstances surrounding the blaze, which is being treated as suspicious.
Anyone who may have information is urged to contact Muswellbrook Police or Crime Stoppers on 1800 333 000.
