FIFA's intelligence agency-style secrecy instills little confidence among football fans, according to ethics prosecutor Michael Garcia.
Garcia called on the organisation's leaders to change the secretive culture at a time when FIFA President Sepp Blatter is under fire for refusing to allow the publication of the American attorney's corruption investigation into the 2018 and 2022 World Cup bids.
The evasiveness has seen the governing body unable to shake off its negative image after being dogged by corruption cases for several years.
"The investigation and adjudication process operates in most parts unseen and unheard,'' Garcia said at an American Bar Association lunch in London.
"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.''
Garcia pointed to the how the International Olympic Committee "moved forward" after publishing the results of a transparent investigation into the 2002 Salt Lake City corruption scandal.
Instead, the fallout of the December 2010 vote that saw Russia awarded the 2018 World Cup and Qatar the 2022 event continues.