Police are investigating following a fire at an industrial site in North St Marys last night.
About 9.50pm on Friday, emergency services were called to Plasser Crescent, North St Marys, following reports a building was well alight.
Fire & Rescue NSW officers attended and extinguished the blaze; however, several businesses were damaged.
No one was at the premises at the time and there have been no reports of any injuries.
Officers from St Marys Local Area Command attended and commenced investigations.
Crime scene examiners will attend the location today and search for forensic evidence.
Police are treating the fire at suspicious and are appealing for anyone who may have information to contact St Marys Police Station on 9677 7499 or Crime Stoppers.