A tandem skydiver who is presumed drowned after crashing into Lake Wakatipu was an American citizen.

The young traveller was the passenger in the last of nine pairs to leave the plane on Wednesday. His pair crash-landed into the lake around 1.40pm.

The tandem master who survived the crash was plucked out of the water after a helicopter pilot who had been flying nearby witnessed the incident and called for help.

Two of his colleagues jumped into a boat and came to the rescue of the tandem master in the water.

The Police National Dive Squad are due to arrive in Queenstown over the weekend to assess conditions and look at the viability of using sonar equipment to help locate the man.

Inspector Olaf Jensen, of Otago Lake Central Police, said the operation was complex, given the depth of the lake.

NZONE director Anthony Ritter spoke to media in Queenstown yesterday about the crash-landing, which happened during one of his company's skydiving operations.

Ritter dismissed as "purely speculative" a parachute malfunction as the potential cause of the crash-landing and said it was too early to determine what caused the fatal accident.

NZONE staff were assisting police and consular officials to try to contact the man's next of kin overseas.

Ritter extended the company's deepest sympathies to the man's family and friends.

"We're all devastated with yesterday's events."

The man had been travelling alone.

NZONE had shut down its operations in Queenstown temporarily and was co-operating with the police and other investigators, including the Transport Accident Investigation Commission.

Another skydiving branch it operated at Wanaka was closed today out of respect but would continue tomorrow.

He said the company would also undertake its own internal review of what happened, adding that staff had been offered counselling.

It was the first fatal incident for NZONE in 27 years he said.

But it is the second accident in 12 months involving the company.

A tandem jump last January ended in a crash-landing with an instructor and trainee instructor suffering serious injuries.