The man found with a missing Victorian teenager in South Australia has been charged with sex and kidnapping offences.

Police tracked down Dean Patrick James, 36, with a 13-year-old girl in Mount Gambier, near the Victorian-South Australian border, around 11am (AEST) on Saturday.

The girl was last seen when she left her home at Ultima, near Swan Hill, on April 17.

James has been charged with one count of attempting to procure a child under 16 for the purpose of sexual penetration and one count of child stealing.

He has been remanded in custody and will appear in a Mount Gambier court on Monday.

The 13-year-old is in police care but is expected to be reunited with her family late on Saturday.