A boy who disappeared two days ago in southern Tasmania has been found alive and well around 100 kilometres from home.

Jack Rumsley, 14, had not been seen since he went for a bike ride around his Woodsdale home, north of Hobart, on Saturday afternoon.

He was found just after 7.00am this morning in the area of Dunalley, approximately 100 kilometres from where he disappeared.

A member of the public spotted the teenager and contacted the police.

Search efforts were ramped up on Sunday after two possible sightings of the boy, who is one of 12 children.