Enhanced Games has launched a $1.2 billion lawsuit against World Aquatics for trying to "crush" the drug-friendly sports event.
Enhanced Games' Australian-born president Aron D'Souza says the lawsuit has been filed in a US federal court in New York.
The suit names World Aquatics, the World Anti Doping Agency and USA Swimming as defendants.
The latter two organisations were included because they supported a World Aquatics by-law, passed in June, that gives the global aquatics body powers to ban anyone associated with Enhanced Games.
"(It's) a thinly veiled attempt to strong-arm the swimming community into boycotting the Enhanced Games," D'Souza said in a statement.
"They're holding elite swimmers and support staff hostage, threatening lifetime bans from Olympic events - all without a single anti-doping violation.
"To claim this is about protecting the 'integrity' or 'health and safety' of athletes is utter hypocrisy.
"This isn't about fair play. It's about a decades-old monopoly desperately trying to crush competition and treat athletes like indentured servants rather than the dedicated professionals they are."
D'Souza said the law suit, in addition to damages, would also seek an injunction to stop the "illegal" campaign from World Aquatics.
Australian swimmer James Magnussen was the first athlete to sign for Enhanced Games ahead of the inaugural event in Las Vegas in May next year.
Australian Brett Hawke has joined as Enhanced Games' head swim coach.
Magnussen is among five athletes to publicly commit to Enhanced Games, a multi-sports event featuring swimming, athletics and weightlifting and no drug testing.
D'Souza, who has financial backing from several multi-billionaires among others, said World Aquatics' by-law was harming Enhanced Games' ability to sign athletes.
The law suit seeks at least $US200 million ($A307 million) in damages, increasing to at least $US800 million ($A1.23 billion) after statutory trebling, punitive damages and the recovery of legal fees.
It was not immediately clear when the US District Court for the Southern District of New York would hear the lawsuit.
