The search for a father who went missing after an attempted rescue went wrong at the edge of Lake Wakatipu continues today, with specialist divers set to join the operation.

Emergency services were first called to Lake Wakatipu at Glenorchy about 2.55pm yesterday.

A man entered the water to assist someone and failed to exit the water himself, a police spokeswoman said.

Boats were searching on the water and helicopters were called to conduct aerial sweeps, the spokeswoman said.

A police officer at the scene told the Otago Daily Times the missing man was a father.

Police this morning confirmed that a number of vessels have been searching the water and helicopters have been doing aerial sweeps.

The police dive squad is due to be deployed this morning.

A Glenorchy resident told the ODT yesterday she understood a father and son got into trouble in the water.

A St John spokeswoman said an ambulance, a first response unit and a helicopter were sent to the scene.

One patient with minor injuries was taken to Lakes District Hospital by road.

A second helicopter was stood down before it arrived at the scene, the spokeswoman said.

An ODT reporter at the scene said there were six boats, including some from Dart River Adventures, on the water searching while a helicopter was on a sandbank near the wharf.

- Oscar Francis and Melissa Ready, ODT