Tickets to the 'Fight of the Century' cost up to $10,000 (£6,591) at the MGM Grand in Las Vegas, according to the Daily Mail.
Manny Pacquiao lost the fight and suffered an injury to the shoulder. The 36-year-old will spend up to 12 months on the side lines as he prepares to undergo surgery on his torn rotator cuff.
Las Vegas residents Stephane Vanel and Kami Rahbaran have filed a class action lawsuit against Pacquiao, suing on behalf of 'all persons who purchased tickets; purchased the pay-per-view event; or who wagered money on the event'.
The pair said he failed to declare his shoulder injury before the fight with Mayweather. It was reported that Pacquiao signed a pre-fight questionnaire without revealing his injury.
Earlier in the week Sportsmail claimed to have seen a copy of the document that shows Pacquiao was taking several painkillers, however it claims the word 'No' is marked next to the question: 'Have you had any injury to your shoulders, elbows, or hands that needed evaluation or examination?'
Stephane Vanel and Kami Rahbaran are seeking more than $5 million (£3.2 m) from Pacquiao, his manager Michael Koncz and his promoters
The lawsuit says "Defendants prior to and at the time the plaintiffs and the class decided to purchase tickets; purchase pay per view showings or wagered on the event the defendants knew and had full knowledge and information that defendant Pacquiao had been seriously injured and was suffering from a torn rotator cuff."
It also stated: "Defendants further know that such injury would severely affect his performance.
"Pay-per-view revenues could top $300 million (£197 million) while ticket revenues for the 'Fight of the Century' have been estimated at around $72 million (£47 million) - even though only roughly 500 tickets went on general sale for the 16,500 capacity MGM Grand venue.
After 12 rounds Pacquiao lost by a unanimous points decision, however the pair say it was not a fair contest because Pacquaio had a hidden injury.
Speaking on ESPN, Daniel Petrocelli, who represents Top Rank, said: "The allegations in this lawsuit are demonstrably false.
"There are documents that explicitly show the medications that Manny was using to treat his shoulder and it was fully disclosed with USADA, which we contracted for this fight.
"This is a frivolous lawsuit and we are confident it will be dismissed."
Bob Arum, Pacquiao's promoter said the injury had healed enough before the match.
Manny Pacquaio said he reinjured his shoulder in the fourth round.
Meanwhile it has been reported Floyd Mayweather said he would welcome another fight with the Filipino.