A man is fighting for life after being dragged unconscious from a burning unit in Sydney’s south.

The fire broke out in a ground-floor unit of a three-level unit block on Seaview St in Cronulla shortly about 10.30am on Friday.

Several people noticed smoke and flames coming from the unit and called Fire and Rescue NSW (FRNSW).

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FRNSW Acting Superintendent Matt Sigmon said crews were met with intense conditions when they arrived.

“A number of crews have entered the unit in what can only be described as challenging conditions — with a high fuel load and thick, hot smoke down to the floor, making visibility close to zero,” he said.

Firefighters had to force their way into the unit and found the man unresponsive in the bathroom.

He was pulled to safety and treated by paramedics before being rushed to St George Hospital.

The blaze was later brought under control.

Sigmon said it may have started in the kitchen, and the unit did not have a working smoke alarm.

No other people were caught in the fire.

Next-door neighbour Daniel Rose said he smelled something burning about 10.15am and saw the black smoke was billowing.

He, along with the building manager, alerted residents to the fire and said he felt “rattled” afterwards.

The cause of the fire is still under investigation.