Mason Lee's stepfather to plead guilty to manslaughter

The stepfather of Caboolture toddler Mason Jet Lee will be sentenced in August over the 21-month old's death.

Lawyers for William Andrew O'Sullivan today requested a sentencing date for the 38-year-old in the Supreme Court, where he is expected to plead guilty to manslaughter.

Mason's death shocked the country in June 2016, when he was found dead by paramedics in a Caboolture house.

The forensic pathologist who examined the boy's body testified that the toddler suffered cruel internal injuries.

Mason had died from abdominal injuries following a heavy blow, which caused his small intestine to rupture, leading to an infection and sepsis.

At the time, he was in O'Sullivan's care.

O'Sullivan was the partner of Mason's mother, Anne-Maree Lee, who has also been charged with manslaughter.

A teenager was able to walk free last month, after his charges were dropped.

Police have alleged O'Sullivan and Lee failed to provide Mason with medical treatment despite his obvious injuries, although it was not clear who inflicted them.

O'Sullivan will be sentenced on August 28.