Melb dad guilty of killing partner's boy

A Melbourne dad has pleaded guilty to killing his partner's three-year-old son.

Brok Ronald Hughes, 26, was charged with murdering the boy but pleaded guilty to the lesser charge of manslaughter in the Victorian Supreme Court.

Hughes told police he grabbed the toddler by the back of the neck and threw him onto his bed, inadvertently causing him to strike his head on the bed frame and wall.

Police say he waited 40 minutes before calling paramedics to tend to the seriously injured child, who later died in hospital.

Hughes was living in a filth-ridden Glenroy home with his partner and her three young children at the time of the toddler's death in May 2014.

The house was littered with used syringes, bloodstains marked the walls and the children slept on mattresses without covers propped up on bricks, according to police documents.

Hughes pleaded guilty to intentionally causing injury and manslaughter of the boy on Wednesday, as well as intentionally causing injury to his younger brother.

Hughes, who also has a child of his own, will face a pre-sentence hearing on April 24.