(CNN) -- Manny Pacquiao is threatening Floyd Mayweather Jr. with legal action following a row over drugs testing which leaves their proposed super-bout next year in doubt.
Pacquiao is refusing to agree to a demand by the Mayweather camp to undergo Olympic style blood-screening in the run up to the fight, which is penciled in for the MGM Grand in Las Vegas on March 13.
Boxing commentators had suggested that the war of words was a pre-fight tactic by the Mayweather camp and his promoter, Golden Boy Promotions, to unsettle the Filipino, who has hit back with an angry statement on his personal Web site.
"Enough is enough. These people, Mayweather Sr, Jr, and Golden Boy Promotions, think it is a joke and a right to accuse someone wrongly of using steroids or other performance-enhancing drugs," it read.
"I have tried to just brush it off as a mere pre-fight ploy but I think they have gone overboard "
Pacquiao, who became a five-weight world champion by beating Puerto Rican Miguel Cotto in November, claimed he would now be calling in the lawyers.
"I have instructed my promoter, Bob Arum, head of Top Rank Inc, to help me out in the filing of the case as soon as possible because I have had people coming over to me now asking if I really take performance-enhancing drugs and I have cheated my way into becoming the number one boxer in the world.
"I maintain and assure everyone that I have not used any form or kind of steroids and that my way to the top is a result of hard work, hard work, hard work and a lot of blood spilled from my past battles in the ring, not outside of it.
"I have no idea what steroids look like and my fear in God has kept me safe and victorious through all these years."
The row started earlier this week when Mayweather's promoters Golden Boy Promotions went public with their demands for blood-testing, as mandated by the United States Anti-Doping Agency (USADA) and making it a condition before the super-fight went ahead.
But Pacquiao's trainer Freddie Roach said this was not necessary under the rules governing fights in Nevada and was mind games by the Mayweather camp.
"We have passed every test ever given to us. We go by the commission rules, since when does the fighter make up the rules?, " he said.
Mayweather himself has largely kept his counsel but told the Golden Boy Promotions Web site that he hoped his possible opponent would change his mind.
"I understand Pacquiao not liking having his blood taken, because frankly I don't know anyone who really does," Mayweather said.
"I hope this is either some miscommunication or that Manny will change his mind and step up and allow these tests, which were good enough for all these other great athletes, to be performed by USADA."
But Pacquiao in his message posted on Christmas Day showed little sign of extending the festive spirit to the unbeaten Mayweather.
"To Floyd, despite all these accusations, may your Christmas be merry and I will see you in court, soon," he added.