The fire, at a home on Madigan Boulevarde about 9:20pm Thursday, claimed the life of 84-year-old Erwin Langthaller and left Mr Langthaller's 53-year-old son in a critical but stable condition.

Father-of-two Jake Bush, 27, was one of several Good Samaritans who tried to make a difference to the outcome.

Alerted to the emergency, he ran straight at it. 

"I tried to open the front door but it was hot so I screamed, 'someone get me something to break it'," he said.   

When a piece of plywood didn't work, he ran home to retrieve a baseball bat.

"I heard the old bloke that lives there moaning, so I smashed [the door] and ran straight through there," he said.

He found the older Mr Langthaller on the floor near the hallway and managed to pull him about two metres before he collapsed and was forced to retreat for a life-saving breath of fresh air. 

For a moment he faced the frightening reality of finding himself in the smoke-filled room, no longer able to see the way out.

"I couldn't see anything ...  I had found him by his voice," he said. 

"I've just kind of grabbed his arms and started dragging him, but he's six foot tall, he's a big bloke, and I couldn't see. 

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"I've panicked and I've breathed too much stuff in and collapsed myself.  It burnt. It was toxic.

"I crawled back out but I couldn't find the door. It was just luck that I found my way out. 

"Then I got another breath and went to go back in there, but the second time I went to go back in there, he wasn't making noises. And then I couldn't find him."

Mr Bush re-entered the home via its back door, certain there were still two people inside. 

He called for them but heard nothing. He looked down at his feet and found they had disappeared in the smoke.

When firefighters arrived soon afterwards they cast powerful torchlight into the home and, from the front lawn, he spotted Mr Langthaller, only about six metres from the home's front entry. 

The smoke made him vomit; a doctor would later tell him the carbon monoxide level in his body was at "seven out of ten".  

He became upset when he learned the elderly Mr Langthaller hadn't survived. 

"I wish I could have done more," he said. "Because I had him in my hands." 

Neighbours say they heard no smoke alarm at the home. 

Shellharbour  firefighter Paul Knight said the property was fitted with one, but it was so fire damaged it was unclear whether it had been operational. 

The home's three bedroom's are located behind one another, along the right-hand side of the property. 

Early reports indicate these were the most fire-affected, and that most damage was in the bedroom farthest back from the street. 

The bedroom containing the 53-year-old man, at the front of the house, was less smokey when firefighters arrived. 

Mr Knight was one of the emergency workers who performed CPR on the residents once they were pulled out unconscious. He said investigators had yet to pinpoint the cause of the blaze.

Mr Knight noted residents had made the task of firefighters easier by creating access to the home before they arrived. 

Lake Illawarra acting inspector Lee Ingmire also paid tribute to the residents and passers-by who helped on Thursday. 

“It’s their brave actions as well as the emergency services that have managed to save the life of one of those male persons,” she said. 

“It's very brave and quick thinking actions. They've put their lives at risk and in doing so they'e managed to save one of the males.” 

Four police officers suffered smoke inhalation, with one requiring treatment at Shellharbour Hospital. He was released last night. 

The critically ill man was transported to Shellharbour Hospital then airlifted to Royal North Shore Hospital, where he remains in a critical but stable condition. 

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