Alexandra Wrage, a Canadian anti-corruption expert, has quit in protest at Fifa's failure to implement new reforms, branding the governing body "an outdated boy’s club".
The news comes on the same day that Nicolas Leoz resigned from Fifa's executive committee for health reasons. The 84-year-old was identified during a criminal trial in 2008 for receiving payments from the governing body's former marketing partner ISL before the company's bankruptcy in 2001.
Wrage was tasked with working alongside the Independent Governance Committee (IGC) in an attempt to restore public confidence in the organisation following a spate of scandals involving internal elections and World Cup hosting decisions.
The IGC was expected to fulfil roles, such as nominating experts for key positions, in Fifa but after a lack of progress Wrage announced her resignation and criticised the organisation in a blog post on Forbes website.
"Blatter has all but declared 'Mission Accomplished', and in a sense it has been," wrote Wrage.
"Opportunities for change have been evaded, finessed or re-directed; he deftly avoids discussion of the recommendations that simply fell off the table over time.
"He did not debate them and did not explain himself; this is no surprise from a man who describes FIFA as if it were a sovereign state over which he presides."
Wrage also revealed how Fifa asked the IGC to stop putting female candidates forward for top positions, stating that no female candidate would be acceptable, before hitting out at the ineffectiveness of the whole process.
She added: "The initiative was declared an effort to restore public confidence in the organization, but has done little more than polish the veneer on an outdated men’s club."