The couple thought that the girl was asleep in the back of the campervan along with the couple's other children. But the distraught girl had been accidentally left behind when the family drove off from a tourist stop near Homer Tunnel in Fiordland on New Zealand's South Island.

A passing van driver noticed the crying girl, who told him her family had driven off without her. The girl knew the campervan registration number, and the van driver phoned police.

The family, including two other children, were oblivious to the missing girl until stopped by police.

"The parents thought all three children were asleep in the back."