An elderly woman has died after her unit went up in flames on Sydney's Northern Beaches overnight.
Emergency services were called to the apartment complex on Lagoon Street, Narrabeen at about 10pm, with around 40 residents needing to be evacuated.
Once the flames were extinguished, the body of the 79 year old woman was located inside.
While the blaze is not being treated as suspicious firefighters, have revealed the unit's smoke alarm was working and it alerted neighbours, but it appears the woman decided not leave.
"Looks like unfortunately the elderly lady did not exit on hearing the smoke alarm and quite possibly tried to extinguish the fire and unfortunately has passed away as a result," Superintendent Greg Rankin said.
"So just a general warning to everyone out there, if you do have a smoke alarm and it operates, please exit and go to a neighbours and call 000 or use your mobile to call 000."