Police are investigating reported sightings of an 11-year-old and his estranged stepfather as far north as Auckland.

The estranged stepfather of a missing 11-year-old boy could be anywhere in the lower South Island, according to the police.

Police say they have confirmed a sighting of the 11-year-old Invercargill boy who is believed to have been taken from school by his estranged stepfather.