A man who woke to find the building he was living in on fire was forced to jump to safety after his exit was blocked by flames.

Firefighters were called to the two storey building blaze around 4.40am on Tuesday.

It took six fire crews around an hour to extinguish the fire, with the last truck leaving the scene at All About Electrics on Koromiko Street in Judea around 11am.

Fire safety investigator John Rewi was called to the scene to investigate the blaze.

He says the man doesn't know what woke him up, but his exit from the first floor was blocked by flames on the stairwell.

'He was very lucky to get out.

'There were no smoke alarms that I can find. There was nothing beeping when the fire brigade got here.

'What woke him up God only knows. He woke up to find the stairs on fire. He had to jump off the floor he was on which is a mezzanine floor - down into the workshop, and made his escape that way through his office.”

John was back at the scene in the Koromiko Street industrial precinct today.

'At the moment I haven't got a cause, so I'm back here today doing it again. I need to have a cause. I can't go away until I have a cause.

'There's a number of scenarios. Because the occupant lives here it could have been a cooking fire. It could have been caused by a cigarette or caused by a number of things actually.

'It all comes down to home fire safety again. If you are living in your home, fit smoke alarms.”

Police have been called to the scene to assist John, but an official investigation has not been launched.