LOS ANGELES (AFP) - Tensions appeared to be rising around the upcoming welterweight world title fight between Manny Pacquiao and Floyd Mayweather, with their camps reportedly at odds over a proposed doping penalty.

Pacquiao adviser Michael Koncz told the Los Angeles Times on Thursday that he was "a little puzzled and dismayed" that Mayweather would not agree to the US$5 million (S$7 million) penalty Pacquiao had proposed should either fighter test positive for a banned drug.

Mayweather Promotions chief executive Leonard Ellerbe, however, told the newspaper that the drug testing protocol for the May 2 fight in Las Vegas had been "rigorously negotiated" by Pacquiao promoters Top Rank.

In comments to ESPN.com, Ellerbe called Koncz an idiot.

"If this moron didn't convey his fighter's wishes when the negotiation was going on, that's their problem," Ellerbe said.

Drug testing was an issue in attempts to put up a Pacquiao-Mayweather fight in late 2009 and early 2010.

Mayweather wanted random Olympic-style blood and urine testing but Pacquiao objected to some of the protocols.

Mayweather later accused the Filipino ring icon of using performance-enhancing drugs. Pacquiao sued over the accusation and the two settled out of court.

Last week, the US Anti-Doping Agency said both had agreed to undergo Olympic-style random drug testing prior to the bout.