By Brian Homewood

ZURICH (Reuters) - FIFA is likely to discover on Sunday if next week's presidential election can go ahead as both candidates, incumbent Sepp Blatter and challenger Mohamed Bin Hammam, face an ethics committee hearing.

The committee, which last year suspended two members of FIFA's executive committee over cash-for-votes allegations involving the hosting of the 2018 and 2022 World Cups, must decide if either man has a case to answer alongside CONCACAF president Jack Warner.

Headed by Namibian high court judge Petrus Damaseb, the hearing's outcome is expected to be announced at about 1600 GMT when a news conference has been scheduled, although it could be delayed.

The presidential election is due to be held on Wednesday at the annual FIFA Congress and delegates from the 208 member associations are likely to start arriving on Sunday without knowing whether there will be a vote.

The investigation was opened last week following a report by FIFA executive committee member Chuck Blazer on a Port of Spain meeting linked to the campaign and involving Warner, Bin Hammam and Caribbean officials earlier this month.

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Blazer's report mentioned bribery allegations while Blatter was included after Bin Hammam said the FIFA president, standing for a fourth term, may have known about cash payments to delegates.

Alongside Asia, CONCACAF, which includes the Caribbean, is the only regional confederation still to announce who it will back for president, the other four having decided to support Blatter.

Bin Hammam, the 62-year-old head of the Asian Football Confederation (AFC), and Warner have denied wrongdoing while Blatter has said that "the facts will speak for themselves."

FIFA has not commented on the possible outcomes although if the committee decides neither candidate has a case to answer, the election appears likely to go ahead.

If both candidates are provisionally suspended, the election would have to be canceled but it is unclear what would happen if one of them is banned and the other given the green light.

FIFA could proceed with the election which would be won by default by the cleared candidate, although there could be complications if the suspended candidate takes his case to the Court of Arbitration for Sport (CAS).

(Editing by Ken Ferris)