Five of the six candidates to host the 2006 Winter Olympics have claimed changes in the bidding process unfairly favoured the Swiss town of Sion. The five said an International Olympic Committee (IOC) ban on members visiting candidate cities gave Sion an advantage in the campaign.

Sion's rivals are Turin (Italy), Helsinki (Finland), Poprad-Tatry (Slovakia), Klagenfurt (Austria) and Zakopane (Poland).

The decision to ban travel by IOC members was part of reforms made to the bidding process following the Salt Lake City corruption and bribery scandal.

Sion, already the favourite to host the 2006 Games, said it was satisfied with changes in the selection procedures under which an electoral college will choose two finalists from the six candidates.

The finalists then face a decisive vote by the entire IOC membership an hour later. The decision is expected to be made at an IOC session in Seoul in June.

Officials from Sion's five rivals said the Swiss town had an unfair advantage since most IOC members visited it when it made an unsuccessful bid to stage the 2002 Winter Games.

They said Sion was also close to IOC headquarters in Lausanne, where IOC members frequently attend meetings.

"We're happy the whole IOC will vote," said Alberica Brivio Sforza, media relations officer for the Turin bid, believed to be Sion's most serious threat. "The only thing we complain about is that the IOC members will not be able to visit our bid.

"Our main competitor (Sion) has had a chance to show what they have to offer. We're at a disadvantage, unable to show what we have.

"We only have photos and nearly all the IOC has visited Sion when they bid for the Games in 2002. They come to Lausanne for meetings and all they see is, Sion, Sion, Sion."

Sion readily conceded it had an advantage but feared a possible backlash might prompt a dirty tricks campaign.

"It is true we have an advantage because they (IOC members) have already visited during our last bid," said Jean-Daniel Mudry, chief executive officer of the Sion campaign. "But we have been trying to get the Games for the last 25 years.

"We would have preferred to have the IOC come and visit because our bid is not exactly the same as before.

"We can't exclude the possibility of a backlash but if something like that happens then we will have to react. It would be sad.

"The IOC has shown today that it is interested in fair play and it would be sad if the candidates did differently. But I can only say we won't get involved in such tactics."