An overheated desk lamp may have caused the fire which killed 11 members of the Taufa and Lale families in Queensland three years ago this week.

A desk lamp fitted with an overly-powerful light bulb could be to blame for Australia’s worst house fire, a inquest has heard.

Eleven members of the Taufa and Lale families, including eight children, died when their home in Slacks Creek, south of Brisbane, was engulfed in flames three years ago this week.

Photographs of the home’s blackened interior were shown at an inquest on Wednesday.

Former scientific police officer Brad Bardell pointed out the remnants of mattresses, couches and electrical appliances, and suggested the fire began in a downstairs study.

“I was of the opinion that the fire had originated in the area of the desk within the office,” he said.

On Monday, the inquest heard from grandfather Tau Taufa, one of three men who escaped the burning building.

Mr Taufa testified that his desk in the study was covered in papers, with space for a desk lamp and glass ash tray.

He recalled working in the room on the night of the fire, before going upstairs for a bath.

Soon after, smoke rose through the kitchen floorboards.

Mr Bardell said a cigarette was a “viable ignition source”, but the lamp could not be excluded.

At the time the lamp was sold, both 40-watt and 60-watt bulbs were available for it, despite the fact it was only approved for 40-watt bulbs.

The more powerful bulbs were banned in November 2009, importers told Mr Bardell.

He said they stopped stocking the bulbs by October 2010, however there was a 12-month grace period for retailers.

While the rating of the bulb in Mr Taufa’s lamp couldn’t be determined, Mr Bardell tested the same lamp with a 60-watt bulb.

“The temperatures and my ability to ignite something like your ordinary 80-GSM printer paper was able to be done within a couple of minutes,” he said.

The inquest was also shown a video of Mr Bardell’s experiment, which the Queensland Fire and Rescue Service hopes to recreate this week.

Counsel assisting the coroner, Simon Hamlyn-Harris, said the family was keen to know if the 60-watt bulbs were sold in the Slacks Creek area around the time.

Mr Bardell said it was unclear.

The inquest continues on Thursday.