The Police Dive Squad is returning to Invercargill tonight as they search for a missing 11-year-old boy and his stepfather.

Mike Zhao-Beckenridge and his estranged step-father John Beckenridge have been missing for around two weeks.

They're thought to be in the Catlins.

Car parts connected to the disappearance have been found scattered along Curio Bay.

Inspector Kelvin Lloyd says dive team members will deploy an underwater camera in the bay tomorrow.

He says it'll be attached to a helicopter, and they hope this will help get visual confirmation of what may be in the water.