Three units were caught up in the blaze which occurred on Davis Avenue, Christies Beach, with fire crews responding to the scene at around 3.30am today.

The fire “completely destroyed” the middle unit and spread to two adjoining units causing “significant damage”, police said, before it was extinguished by Metropolitan Fire Service crews.

The occupant of the middle unit, a 72-year-old man from Christies Beach, sustained minor burns. There were no other reported injuries, police said.

The man is expected to be arrested and charged with arson this morning, police said, and will face the Christies Beach Magistrate Court on Tuesday.

Earlier, fire crews responded to an unoccupied unit fire on Rundle Street in Kent Town at around 2.50am today.

Police say MFS crews were able to contain the fire to a bedroom and evacuate residents in adjoining units before any structural damage was caused.

Police say the Christies Beach and Kent Town fires are not linked. Crime scene investigators have attended the scene to determine the fire’s cause.

Man seriously injured after motorbike crash

Meanwhile, a man has been taken to hospital with life-threatening injuries after a crash between two motorbikes on the Fleurieu Peninsula on Sunday.

Police say they were called to Bull Creek Road in Tooperang around 1.40pm yesterday following reports of a crash between two Harley Davidson motorbikes.

One of the riders, a 62-year-old man from Gilles Plains, was transported to the Flinders Medical Centre with life threatening injuries.

The other rider, a 49-year-old man from Sellicks Beach, was uninjured, police said.

Bull Creek Road has since reopened after being closed for several hours on Sunday afternoon as Major Crash Investigators examined the scene.