Strauss-Kahn said on Thursday that it was ``more and more probable'' that airlines would take such a step to avoid potential disaster from the effect of the bug.

Computer experts fear widespread chaos because many older computers will be sent haywire because their inbuilt clocks will mistake the arrival of 2000 for a reversion to 1900. Junior Industry Minister Christian Pierret agreed that malfunctions could happen, though he added that grounding of planes would be ``a worldwide decision after coordination with all the civil aviation authorities.''

The management of the French authority dismissed the forecast as an excessively pessimistic disaster scenario, adding that the airline industry had been working on the problem since 1997. Dominique Alvarez, head of the authority's Year 2000team, said ``each company will decide what it does. It will not be states which decide if there are flights or not.'' By July 1, 1999 all member states of the International Civil Aviation Organisation (ICAO) would have to make public what they had done to meet problems related to the change of year, he added. The International Air Transport Association (IATA), which groups airlines, had set up a 20-million-dollar programme to provide its members with details of how prepared countries, airports and civil aviation departments are. This programme would analyse every detail, down to the computers handling the baggage retrieval conveyors, an expert said.

``A possible scenario would be that companies cancel certain flights to certain destinations, depending on the state of their preparation,'' he added. In France, revised computer systems which provide radar images to air traffic controllers should be installed in control centres by the middle of next year. Civil aviation authorities are also seeking assurancesfrom plane builders and equipment suppliers that their computers are able to handle the change of year date. Airbus Industrie, the European consortium whose airliner assembly plant is at Toulouse, southern France, said a series of trial flights had confirmed that its planes would not be affected. ``Nothing likely to have an impact on the navigability or operation of the aircraft has been detected,'' a spokesman said. ``Only a few minor anomalies, on non-critical equipment, have been found and solutions will be proposed before January 1, 1999 , when it must be certified fit for 2000.''

Airbus added that very little equipment aboard its aircraft possessed all the four functions which together might pose problems: carrying out digital calculations, knowing the date, storing it in an abbreviated form and using it in calculations. France's state-owned airline Air France, almost visibly irked by Strauss-Kahn's comments, said stiffly: ``We will make sure our planes fly and there is no bug.''