"The WBO world championship committee is allowed no other alternative but to cease to recognize Mr Floyd Mayweather Jr as the WBO welterweight champion of the world and vacate his title for failing to comply with our WBO regulations of world championship contests," the WBO said.
"The WBO has the utmost respect for Floyd Mayweather Jr and all that he has accomplished during his storied career. Mr Mayweather has always agreed with and understood that world championships have both privileges and responsibilities and that status as WBO champion is subject to and conditioned on compliance with the WBO rules and regulations."
Mayweather is still welterweight and super welterweight champion for the WBC and WBA, even though boxers are not allowed to hold world titles in multiple weight classes.
Mayweather is expected to fight for the 49th and possibility last time in September and Mundine - the mandatory challenger for the American's WBC super-welterweight title - has taken the extraordinary step of writing an open letter begging boxing's pound-for-pound king to pick him as his next opponent.
Mundine, the current WBC silver super-welterweight champion, was due to fight Austin Trout in a rescheduled bout but negotiations collapsed.
And now Mundine has challenged Mayweather to step into the ring and take on "the uncrowned best athlete of all time!".
Addressing Mayweather as 'My man Floyd', Mundine boasts "I'm the wonder from down under & the only one that can solve the mayvinchi code" before going on to say the fight would be 50/50."
Mayweather has so far dismissed the chances of many high-profile names such as Amir Khan, Gennady Golovkin, Kell Brook and Shawn Porter.
Instead, Mayweather has continued to insist that he will fight either Karim Mayfield or Andre Berto.
But Mundine insists that as mandatory challenger he should be considered.
He said: "I've got other attributes that none of these cats got! Makes for a good boxing spectacle both in and outta the ring. Its what the boxing fans need to see!
"You want show time - I am show time! Somebody the world needs to see! I'll give you a way better go than you been getting!
"It's a 50-50 fight. Best athlete v best fighter??? Both got fast feet fast hands & fast mouth haha ...or relinquish the Title as you're preventing fighters like me in this position to take on the other champions or the bigger names in sport!"
Mundine was the highest paid player in the NRL when he switched to boxing in 2000 and, despite having no amateur experience, has amassed a professional record of 47 wins and six losses.
The 40-year-old has notable wins over Shane Mosley, Daniel Geale and Pablo Daniel Zamora on his record but has lost to Joshua Clottey and Mikkel Kessler during his career.
Mundine's last bout in November 2014 saw him win a split decision over then undefeated European champion Sergey Rabchenko to claim the WBC silver super-welterweight title and become Mayweather's mandatory challenger.
