Once the most powerful man in the US football, Chuck Blazer, is now being revealed to be an FBI informant employed to spy on Fifa, New York Daily News has reported.

In a report published over the weekend, it is alleged that Blazer was pressurised into working for the FBI after he failed to pay millions of dollars in income taxes that he had earned while working as a leader of CONCACAF, football's governing body for North and Central America and the Caribbean.

Blazer had earlier resigned from Fifa's executive committee in 2013 following a CONCACAF audit finding that revealed he had received millions of dollars in undeclared commissions.

He has since acted like a 'whistleblower' and uncovered the Caribbean vote-buying scandal that led to the expulsion of his CONCACAF colleague Jack Warner and FIFA vice president Mohamed Bin Hammam in 2011.

Presently, Fifa's bidding process for 2018 and 2022 World Cups, is under a corruption probe, led by Michael Garcia, a former US prosecutor.

Garcia has submitted his investigation findings to Fifa, however, Fifa has chosen not to release the full report due to legal reasons.

It is alleged that former head of Qatari soccer, Hammam, had paid several national federation chiefs to back Qatar, paving way for the nation winning the right to host the 2022 World Cup.