Police have named a three-year-old Auckland boy who died after being trapped in a van which was submerged in Lake Dunstan, near Cromwell yesterday.

He was Aarush Macwan.

A 32-year-old relative of the child has been charged with careless driving causing death and will appear in the Alexandra District Court next Wednesday.

Acting Central Otago police sub-area supervisor, Sergeant Mike Williams said the Toyota Hiace van, parked on the side of the lake, rolled forward and became submerged in about 5m of water, with five passengers still inside.

It plunged over a 5m rocky outcrop before landing in the lake.

Four adults and an 11-year-old child managed to escape from the van but attempts made by the occupants to unbuckle the three-year-old boy were unsuccessful.

Passersby also tried in vain to retrieve the child.

Volunteer fire brigades from Tarras and Cromwell attended the accident and a Cromwell fireman, John Searle, who is also a diver, used breathing apparatus to recover the boy from the van.

"CPR was attempted once he could be brought to shore, but he died at the scene, " Sgt Williams said.

The passengers of the van received medical treatment at a nearby medical centre but were not admitted to hospital.

Travelling in the van were an Auckland family and three overseas visitors. They were on holiday, heading to Queenstown.

Mr Searle said the van was resting on a shelf, about 5m under the surface of the lake. The young boy was still strapped into his car seat when he recovered him.

Visibility was good in the lake, with the water clear but very cold, he said.

- Otago Daily Times