Forensic investigators are combing through evidence at Torton Place in Penrith this morning following a unit fire.
Fire crews were called to the blaze at around 5.30am this morning, finding a second floor unit well alight.
Nobody was injured and local evacuations took place.
More than two dozen firefighters worked to bring the blaze under control. Eight fire trucks responded.
Firefighters worked to ventilate the area of the smoke left behind by the fire.
A short time ago, forensic teams from the NSW Police were seen at the site of the fire, as an investigation is launched into the cause.
The Weekender understands a number of residents have been displaced as a result of the fire, with local charity the Ross Hutchison Foundation offering vouchers and clothing.