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.