An Air New Zealand Airbus A320 aircraft on a test flight crashed into the sea off France's southwest coast on Thursday, killing at least one person with a further six still missing, authorities said.

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

It said an investigation had begun but it said it was too early to provide an explanation for the crash.

"Seven people were involved. We have recovered one dead body," a spokesman for the Pyrenees-Orientales prefecture, in southwestern France said.

The A320, a twin-engine, single aisle aircraft that normally seats around 150 passengers, is manufactured by Airbus, a unit of European aerospace group EADS.

The Pyrenees-Orientales prefecture said the plane was on a "technical flight" and was being serviced by a company based in Perpignan.

The aircraft, built in 2005, had been leased by Air New Zealand to German carrier XL Airways for the past two years and was being tested after a refit prior to being returned to its owner, a spokesman for XL Airways said.

Two German XL Airways crew and five Air New Zealand test engineers were on board.

"At this point we do not know exactly what happened. At first we heard the plane had managed an emergency landing on water but then the coast guard said the plane had broken apart," the spokesman said.

Air New Zealand said the aircraft was due to return to service with the company next month.

Airbus said the aircraft, delivered in July 2005, had accumulated approximately 7000 flight hours in some 2800 flight cycles. Around 1,960 A320 aircraft are in service with 155 operators around the world.

It said would assist authorities investigating the crash but it added it would be inappropriate to speculate on the causes.