Tasmania Police mentioned emergency companies discovered the shed absolutely alight on Verdun Avenue within the Launceston suburb of Mowbray simply after 1.30pm in the present day.
"A toddler was discovered deceased, and one other younger youngster was taken to hospital with critical accidents," police mentioned.
"An grownup was additionally taken to hospital with non-life threatening accidents."
Tasmania Fireplace Service is investigating what brought on the hearth and a police report can be ready for the coroner.
"Our ideas and condolences are with everybody affected," police mentioned.