Tranmere property gutted in 'deliberately lit' blaze

Ten people have been left homeless after a deliberately lit blaze gutted an Adelaide home, in the second attack on the property in three days.

Resident George Flower told 9NEWS that two men knocked on his door demanding money in the moments before the Tranmere house was engulfed in smoke.

"He said 'do you owe anybody money?' and I said 'nah mate'," Mr Flower said.

"And then the fire alarm went off and neighbours started yelling out."

Fire fighters rush in to attack the blaze but there was little they could do to save the structure.

Residents fled as neighbours alerted them to the flames.

"It was red hot – I had to back off because the smoke was too thick," Mr Flower said.

The property is divided into multiple units. With up to 10 people living there, fire crews immediately began a search to make sure no one was left inside.

"That made it very challenging for us to conduct a search for any unaccounted persons," Acting Commander of the SA Metropolitan Fire Service Gideon Douglas said.

"Our number one priority outside of doing a primary search was to protect the property next door."

The blaze breaking out at the front of the property around 8am.

Those living in neighbouring properties were told to shut their windows and doors, as fire crews feared the blaze could spread.

Police have launched an investigation into how the blaze took hold.

They are investigating whether there are any links to a firebomb attack just two days ago.

Fire fighters say the home is now uninhabitable and what is left of the structure will have to be torn down.