A leading FIFA anti-corruption adviser resigned Monday, claiming football's governing body failed to change its culture after bribery and vote-buying scandals.

Alexandra Wrage, the president of international compliance expert TRACE, left an advisory panel chaired by Swiss law professor Mark Pieth which was asked to guide FIFA President Sepp Blatter's promised modernizing reforms.

"[FIFA] remains the closed society that fueled its problems to begin with," the United States-based not-for-profit group said in a statement.

Wrage leaves Pieth's team after it pledged to increase its FIFA work when it met in Switzerland last week for a final scheduled session to decide strategy ahead of a FIFA congress on May 31 in Mauritius.

Pieth, who has had increasingly testy relations with Blatter and his organization, said they will monitor FIFA beyond the congress.

"[The panel] discussed all options and unanimously arrived at the conclusion that FIFA continues to need a compliance watchdog after the Congress of 2013 for the remaining reform steps, amendments, and especially for the implementation of the reform program," Pieth said in an email statement to The Associated Press.

Blatter has suggested Pieth's mandate should end at the congress.

"Since this means an intensive workload for the [panel] for the year 2013-14, Ms. Wrage has decided to leave the group," wrote Pieth, a former United Nations investigator.

In Mauritius, FIFA member countries will be asked to approve a slate of reforms agreed to by Blatter and his executive committee last month.

Wrage has previously spoken out in frustration about the FIFA board's rejection of some modernizing proposals, including women candidates for high-profile appointments and greater transparency about salaries and bonuses paid to Blatter and other senior officials.

"The [advisory panel] made recommendations that ultimately amounted to nothing more than common sense text book corporate governance and best practices in compliance, but even those were never considered by FIFA," Wrage's group said in its statement on her behalf.

FIFA declined to comment on Wrage's resignation.