Man rescued from blazing Sydney house

Julia Carlisle

A man who was pulled from a burning Sydney house is fighting for life with severe burns after two council workers who raised the alarm tried in vain to break into the residence.

The two used their truck to break down a fence to access the yard after spotting the Seven Hills house on fire at 6.20am on Wednesday.

They weren't unable to enter the home due to the intense smoke and heat but firefighters were able to get inside and pull out a 41-year-old man who was on the floor in a back room, police said.

He was carried to safety and treated at the scene before being taken to Concord Hospital in a critical but stable condition, suffering burns and smoke inhalation.

One of the council workers has been checked as a precaution after suffering shock.

Seven fire crews are on the scene, along with a fire chief, and have contained the blaze which caused extensive damage to the home.

Forensic officers and investigators will work to determine the cause of the blaze when the location has been deemed safe, Fire & Rescue spokesman Norman Buckley told AAP.