Just after 7am, Fire and Rescue NSW were called to an automatic fire alarm at Emmaville Hospital, on Glen Innes Road.

Crews from Glen Innes Fire Station arrived to find 30 staff and patients had been evacuated, and noticed there was a smell of burning in the building.

RFS crews were already on scene conducting initial investigations into the blaze, which was contained to the hallway.

Upon further investigation, crews determined an electrical fire had occurred in the ceiling.

"The results of the investigation concluded that the small fire was caused as a result of the burnt out ballast in a fluorescent lighting unit," Glen Innes Fire and Rescue captain Earl Sharman said.

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The smoke triggered the alarm causing the hospital to undergo its evacuation process.

"All occupants were evacuated safely with no injuries," Mr Sharman said.

"The evacuation process conducted by the hospital was done well, good result from all services involved."

After finding the source of the fire the light fitting was isolated, and the smoke was ventilated from the building.The air quality was then tested to ensure it was safe before allowing patients and staff to return.

"The fire was under control by 7.30am, with the RFS located next to the hospital, there was a quick response time," Mr Sharman said.

Mr Sharman said no structural damage was caused to the building.

NSW Police, and NSW Ambulance also attended the scene.