FIFA presidential favourites Sheikh Salman bin Ebrahim al-Khalifa and Gianni Infantino look set for a tense battle at the polls following a final day of campaigning before Friday's election.

The UEFA general secretary and chief of the Asian Football Confederation remain the leading contenders to succeed former president Sepp Blatter at the Extraordinary Congress in Zurich, ahead of Prince Ali bin al-Hussein, Jerome Champagne and Tokyo Sexwale.

Delegates arrived in Switzerland for the meetings of the separate confederations, at which the candidates were allowed to lobby for support in a final attempt to boost their campaign profiles and win over undecided member associations.

Infantino, whose plans to offer associations $5million to invest were accused of endangering FIFA with bankruptcy by Sheikh Salman, wrote to the presidents of all associations to dismiss the arguments and reiterate his commitment to reforming an organisation marred by corruption investigations in the past year.

The Swiss is set to count on the support of UEFA and, he insists, a number of African votes, despite claims from the Ghana camp that the Confederation of African Football will overwhelmingly back Sheikh Salman. Members of CONMEBOL are also expected to back Infantino, with Brazil's World Cup-winning captain Cafu lending vocal support to his campaign.

"I am not a politician," he said. "I am somebody who loves football. I'm very confident."

Sheikh Salman, who was forced to deny allegations made by a British MP this week that he used FIFA-backed development funds in order to finance his election bid, finished Thursday in a strong position after the East Asian Football Federation - comprising nine nations - declared its support.

That followed CAF vice-president Suketo Patel's assurance that Asia - considered, along with Africa, a strategic gold mine in the final election - will vote "as a bloc" for the 50-year-old Bahraini prince.

Salman also moved to assure supporters of the controversial World Cups in Russia and Qatar in 2018 and 2022 that he would not strip them of the right to host the tournaments unless clear criminal action in their bidding processes is proven.

"Unless it is proved there is criminal activity involved then every country has the right to host the World Cup. But it has to abide by workers' and human rights and proper international standards," he said.

"If I was president I would make sure they stick with their work and implement what they they have to do."

Outsider Champagne took a swipe at Infantino's globe-trotting campaigning in recent weeks, quipping to the media: "I did not have a private jet to visit you, take a photo and then tweet and say I have got the endorsement."

Jordanian Prince Ali described Friday as "the biggest milestone in the history of FIFA. It will decide if FIFA goes ahead as we want or if it spirals down". Ali - backed by Champagne - had appealed to the Court of Arbitration for Sport to have transparent voting booths used for the election in order to underline a quite literal commitment to transparent voting. This was rejected on the grounds that security and integrity measures are already in place.

South Africa's Tokyo Sexwale, who described FIFA as "broken" has resisted calls to abandon his campaign due to a lack of support and remains distinctly unlikely to threaten.

Regardless of the outcome in the search for Blatter's successor, FIFA faces a defining day. Acting president Issa Hayatou has already urged all member associations to back proposed reforms at Friday's polls in a bid to start to repair the crippling damage dealt by the anti-corruption investigation and global outcry for change in the past year.

"The eyes of the world are on us," he said. "This will send a strong message that we have listened."