Bruises found on leg of baby who died

Child protection workers found extensive bruising on the thigh of a 10-day-old Tasmanian boy, who died a month later from head injuries, an inquest has been told.

Bjay Johnstone was just 45 days old when he died in November 2012 and child protection worker, Chree Eberhardt, on Thursday gave evidence about her interaction with the new parents, who had been the subject of an alert due their homelessness and cannabis use.

During an unannounced visit to Bjay's grandmother's house, where the new family was staying, Ms Eberhardt and a colleague noted a bruise on the underside of the baby's thigh.

"(Father) Simon said he got up to feed Bjay and didn't switch on a light so as not to disturb his brother who sleeps on the couch, and walked into a door," she said.

The child otherwise appeared clean and well wrapped, Ms Eberheardt said.

Mr Johnstone has been sentenced in the Supreme Court for ill-treating Bjay, but the injuries he caused are not linked to the death.

The inquest before coroner Olivia McTaggart continues.