FIFA ethics investigator Michael Garcia criticised the organisation's lack of transparency on Monday and urged it to publish his report into the bidding process for the 2018 and 2022 World Cups.

Garcia has written a report into corruption allegations concerning the attribution of hosting rights for the tournaments but FIFA president Sepp Blatter says publishing it would compromise witness confidentiality.

Speaking at the ABA Criminal Justice Section International White Collar Crime Institute conference in London, Garcia said: "The investigation and adjudication process operates in most parts unseen and unheard.

"That's a kind of system which might be appropriate for an intelligence agency, but not for an ethics compliance process in an international sports institution that serves the public and is the subject of intense public scrutiny."

The American lawyer added: "Transparency is not intended to embarrass certain individuals by airing dirty laundry or to harm the organisation by showing what went wrong. It's the opposite.

"Where the institution has taken significant steps forward and made that progress, transparency provides evidence of that to the public."

Russia won the right to host the 2018 World Cup and Qatar was awarded the 2022 tournament after a joint-bidding process that was overshadowed by accusations of corruption and horse-trading.

Several high-profile figures have called for world governing body FIFA to publish Garcia's report, including UEFA president Michel Platini and FIFA vice-president Prince Ali Bin Al Hussein.