PARTS of Mururoa, the South Pacific atoll which has been subjected to nearly 200 French nuclear tests, are in danger of sinking as a result, the French authorities admitted for the first time yesterday.

 The admission is a change of direction for the French authorities, which until now have categorically denied the existence of cracks and faults on Mururoa. In 1995, the French foreign minister threatened Le Monde newspaper with legal action after the newspaper reported huge cracks and published a military map showing faults criss-crossings the atoll. The map appeared to confirm the concern of independent French scientific missions to the Pacific atoll in 1982, 1983 and 1987. The last, led by Jacques-Yves Cousteau, warned the island was in danger of breaking up and releasing radioactivity.

 France has carried out 193 nuclear tests on its Polynesian possession since 1962. Of these, 137 were detonated underground between 1975 and 1996. Experts are worried about the north-eastern part of the atoll known as Colette, where 28 underground tests were carried out during this period. Large stretches of land are now threatened with subsidence.

 "We are now witnessing an acceleration of the natural movement towards the ocean of certain outer areas in the north-eastern zone of Mururoa, in addition to subsidence on the surface," admitted a spokesman for nuclear safety at France’s Atomic Energy Commission. "A certain fragility of the atoll has been amplified by nuclear tests," he added.

 The statement, published yesterday in France-Soir, is a first for the French authorities.

 As early as 1979 there were two instances of land collapsing into the sea in the north-east of Mururoa after a nuclear test exploded too soon, injuring several people. The population of the atoll has not forgotten their fear when they witnessed the mini-tidal wave produced by the explosion.

 "Today, everything is monitored in real time," the Atomic Energy Commission spokesman told France-Soir yesterday. Seismic sensors have been installed at strategic sites on the atoll to warn Paris directly in case of subsidence.

 "The problem is that the Polynesians will be the last to know," said Bruno Barillot of the Observatory of French Nuclear Arms. "And despite all the good intentions, anxiety is increasing here among the local population."

 In 1998, a government-ordered report from the International Atomic Energy Agency into the health hazards of nuclear tests shows Paris was aware of subsidence three years ago. While the agency reported that "no effect on health, no corrective measures are necessary on the atolls", it also found that "underground nuclear tests have caused a destabilisation in the atoll of Mururoa."

"Depending on the site of the subsidence, a certain level of radioactivity may be released into the ocean," it said.