A shark savaged an Australian kitesurfer to death off New Caledonia on Tuesday in the second fatal attack in the South Pacific territory in six months, officials said.

"The man in his 50s was kitesurfing inside the reef at Koumac. He fell and was bitten," Nicolas Renaud, head of the archipelago's marine rescue coordination centre, told AFP.

The unidentified man from Fremantle on Australia's southwest coast was out with several other people on a catamaran, who raised the alarm.

A rescue boat was sent to help but emergency crews were unable to save him.

"He suffered a deep bite to the thigh from a big shark. We don't know for the moment what species it was," added Renaud.

The last fatal shark attack in New Caledonia, a French territory east of Australia, was in April, when a woman was killed on a beach on Poe in the west of the island group.

There were 98 shark attacks globally last year -- the highest number ever recorded, according to researchers at the University of Florida, which has been collecting data since 1958. Six of the attacks were fatal.

Theories on the increase include rising water temperatures caused by climate change making sharks change their habits, the El Nino weather pattern, which was particularly powerful last year, and the increasing popularity of watersports.