Police are hoping to recommence the recovery of the car linked to the disappearance of an 11-year-old boy in Southland.

A search has been underway for Mike Zhao-Beckenridge and his stepfather John, since the middle of March.

The Police National Dive Team will fly to Invercargill tomorrow where they'll be coming up with a plan to recover the blue Volkswagen found in the waters at Curio Bay at the start of last month.

Inspector Kelvin Lloyd says tidal forecasts show the weather will be calm enough for the dive squad to enter the water on Wednesday and attach floating equipment to the car.

He says the car, and what may be inside, remains a crucial part of the investigation.