Police are questioning a man after a fire in West Pennant Hills yesterday uncovered a number of mature cannabis plants.

Emergency services were called to a house on Oakes St about 6.20pm on Tuesday. Fire & Rescue NSW firefighters extinguished the blaze, which caused only partial damage to the building.

During a subsequent inspection of the premises, police located being grown inside the building.

A man was arrested at the scene and is assisting police with their inquiries at Castle Hill Police Station. An investigation is underway into the circumstances surrounding the fire.

Anyone with relevant information is asked to contact police.

Police are urging anyone with information about this incident to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page: https://nsw.crimestoppers.com.au/ Information you provide will be treated in the strictest of confidence.