FIFA Vice President Michel Platini has raised the prospect of a walkout by Asian members in Wednesday's presidential vote.
Incumbent Sepp Blatter is the only candidate in the election after Asian Football Confederation President Mohamed bin Hammam withdrew his candidacy before being suspended by FIFA over bribery allegations.
Platini, the president of UEFA, reminded members of European football's governing body at a meeting in Zurich Monday of Asia's protest at a 1999 congress over World Cup places.
''In '99 Asia left, I don't know if they will do that again. I think the election will go ahead but I don't know,'' Platini said.
Blatter is unconcerned about the 46 Asian members disrupting the meeting on Wednesday when world football's 208 countries are due to vote.
''I have already faced that once and the Congress went on,'' Blatter said. ''They will be there I am sure.''
On Monday, the AFC canceled its caucus meeting scheduled for Tuesday morning without explanation. It is the only one of FIFA's six confederations to skip the traditional pre-congress gathering.
Yousuf Al Serkal, an AFC vice president and close ally of bin Hammam said the Qatari had been ''mistreated.''
''Bin Hammam is the right person who should have been elected to the presidency of FIFA from the point of view of change,'' Al Serkal told The Associated Press. ''Blatter has had his chance, it's more than enough. There should have been changes for the benefit of football.
''Bin Hammam could have been the best to serve world football at this time. The way he was treated I think it was unfair. All the allegations were just from a report.''
A FIFA ethics panel said Sunday that there was sufficient evidence to further investigate allegations that bin Hammam as well as CONCACAF President Jack Warner offered $40,000 bribes to delegates at a Caribbean football association meeting earlier this month ahead of the election.
In a statement issued early Tuesday morning, the AFC backed bin Hammam and confirmed that its most senior vice president, China's Zhang Jilong, will be acting president of the confederation.
''We, the members of the AFC Executive Committee, express our deepest concern at the latest developments within FIFA and that involves the AFC President Mohamed Bin Hammam,'' the statement said. ''We will be following the investigation as it takes its course. We hope the outcome of the investigation will be in the best interests of football in Asia and beyond.''
AP Sports Writers Michael Casey in Dubai, United Arab Emirates, and John Pye in Brisbane, Australia contributed to this report.