An Air New Zealand Airbus A320 on a test flight crashed into the sea off France's southwest coast on Thursday, killing at least two people with five still missing.

France's BEA civil aviation safety authority said the crash took place at 4:46 p.m. (1546 GMT) when the aircraft, made by the Airbus unit of European aerospace group EADS, was approaching the airport at Perpignan, in southwestern France, after a flight that had lasted about an hour.

A witness told French radio he saw the plane dive abruptly and plunge into the Mediterranean sea.

"I could see it was an airliner because I saw two large engines. There was no fire, nothing," the witness, a local policeman, told France Info radio.

"It was flying straight, then it turned brutally towards the ground. I said to myself it will never pull out and there was a big spray of water," he said.

Five New Zealanders and two Germans were aboard the aircraft, which had been leased to German carrier XL Airways and was being tested after a refit before returning to New Zealand next month.

A search team of five French Navy ships would continue to scour the area through the night, although the weather conditions remained poor, Air New Zealand chief executive Rob Fyfe told a media conference in Auckland.

Two bodies have been recovered but the chances of finding survivors were slim, given the length of time since the crash and bad weather in the area.

"We won't give up hope, but the search and rescue authorities are not optimistic, given the conditions, of finding any survivors," Fyfe said.

Specialist divers were to swim down to the wreck of the plane at first light to try and retrieve the flight recorder and any bodies that may be trapped in the wreckage.

The aircraft was sitting in shallow water, with the tail of the plane visible from the surface.

The crash occured exactly 29 years after New Zealand's worst-ever air crash, when an Air New Zealand plane on a sightseeing trip in Antarctica hit the side of Mount Erebus, killing all 257 people on board.

"To have this incident occur on the same day just adds to the sense of tragedy," Fyfe said.

The A320 is a twin-engine, single aisle aircraft that normally seats around 150 passengers. About 1,960 A320 aircraft are in service with 155 operators around the world, Airbus said.

It said the aircraft, powered by IAE V2500 engines, was delivered in July 2005 and had accumulated approximately 7,000 flight hours in some 2,800 flight cycles.

Airbus said it would assist authorities investigating the crash and had sent five specialists to the site, but it added it would be inappropriate to speculate on the causes.

Air New Zealand's Fyfe has also declined to speculate on the cause of the crash.