Jack Mitchell, 21, had been heading to the pub with a mate after a footy game when they saw flames about a metre high in the front room of someone's home.

A woman who had fled the building was outside with people comforting her, but emergency services had not yet arrived.

"We were just standing there watching for about five minutes," Jack said. "The lady had said no one was inside, but then a man came running up and told us another family was next door."

The building was divided into two residences, and one of the bystanders smashed a window on the left hand side and climbed in.

Jack isn't sure if that man unlocked the door or not, but it opened when he tried it and he ran inside too and started shouting.

"By that stage the house was well alight and the door had started to catch fire," Jack said. "I was in the hallway yelling 'Get out of the house!'"

Watch and listen to Jack's video of the fire:

Three or four panic-stricken people, including a teenage girl, rushed out just before the whole building became engulfed in flames.

"About thirty seconds after they got out, the whole house was on fire - nobody would have been able to get in or out," Jack said.

"It was about 11 or 11.30 at night and I'm guessing they were asleep and had no idea."

Jack said one of the women was treated for smoke inhalation but there were no other injuries.

The building suffered an estimated $1.4 million worth of damage.

Jack described it as "a pretty intense experience" but said he hadn't felt frightened.

"I didn't really feel in danger. My heart was pounding and there was a lot of adrenalin, but I didn't think I'd be burned so I wasn't scared at all. I was only in there briefly."

Jack's family live in Brierfield and he went to Bellingen Public and Bellingen High before enrolling at Newcastle Uni to study primary teaching.

He's a keen sportsman who played junior and senior rugby league with the Magpies, AFL with the Bulldogs and cricket for Bellingen as well.

He plans to return home within the next year after completing his degree and then save up to go travelling.