A mother was made to sit on a couch and watch her son being bashed to within an inch of his life by her boyfriend, a Queensland court has heard.

A Queensland woman was forced to sit on her couch and watch her son being fatally beaten by her boyfriend, a court has heard.

Susan Davis, 43, was allegedly made to sit and watch while her unconscious son was bashed to within an inch of his life by her 24-year-old boyfriend.

Cameron Joseph Bani, now 26, allegedly told his then-partner of 12 months, “watch what I’m going to do to your little boy next” before beating her 22-year-old son in the head with a cooking pot.

Bani has pleaded not guilty in the Brisbane Supreme Court to murdering Deon Davis in May 2012 at Browns Plains in Logan, south of Brisbane.

Crown prosecutor Todd Fuller said Bani killed Mr Davis after two days of simmering tension between the pair.

Mr Davis had recently moved into his mother’s house, where Bani also lived.

Bani allegedly said he was going to put Mr Davis in hospital hours before the pair argued and Mr Davis was knocked unconscious.

Mr Fuller said Bani straddled the unconscious man and bashed him repeatedly while his mother watched in horror, before Bani grabbed a cooking pot from the kitchen.

“He poured the contents which was just water over the back of Deon Davis as he lay unconscious on the floor,” Mr Fuller said.

“He then struck him in the head with it. He then struck him … a number of times before he then rolled him back over, picked up a pair of thongs and struck him about the face with them.”

Mr Fuller said Bani called and ambulance after it became apparent Mr Davis wasn’t breathing.

He suffered irreversible brain damage, his life support was turned off and he died in hospital the following day.

An autopsy revealed 39 separate injuries including heavy facial bruising and a broken nose, jaw and teeth, as well as bleeding in the brain and other internal injuries.

Bani, who suffered only minor injuries, told police he’d been forced to defend himself against repeated attacks from Mr Davis.

Defence barrister Dennis Lynch urged the jury to consider Bani’s version of events.

The trial is expected to run for five days.