LOS ANGELES • A trio of world and Olympic champions has sued Fina over its crackdown on non-approved events, challenging what they allege is the monopoly that swimming's world governing body has over the control of international competitions.

The Hungarian star Katinka Hosszu and Americans Tom Shields and Michael Andrews filed the class-action anti-trust lawsuit in a San Francisco court on Friday, after Switzerland-based Fina effectively shut down a new professional event scheduled for Dec 20-21 in Turin.

The Italian federation said Fina threatened the swimmers with sanctions, including banning them from Olympic competition.

The event was coordinated by the organisers of a proposed International Swimming League (ISL) that would operate outside Fina's control and pay higher prize money.

Shields, an Olympic gold medallist, said he joined the lawsuit because he had, for years, dreamt of seeing swimming expand to include a professional league.

"We are closer now than ever before to making that dream come true," he said. "But that dream is being blocked by Fina."

Attorneys for the plaintiffs say the swimmers "believe a professional league that will compensate its best athletes and better reward them for a lifetime's worth of hard training and sacrifice is long overdue".

The lawyers said that the ISL had filed a separate lawsuit against Fina for its allegedly "anti-competitive conduct".

Although neither lawsuit challenges Fina's authority to operate as the gatekeeper of the Olympic Games, the lawyers said, they allege that Fina "unlawfully wields that power to prohibit swimmers from participating in non-Fina events or in any events that Fina does not formally approve".

The world governing body, in a statement, said it had taken note of the filings in California.

"As world and Olympic champions, the swimmers in question will understand that Fina's attention is focused on the 950 swimmers, including two of the athletes in question, from 180 member federations taking part in the 14th World Swimming Championships (25m) in Hangzhou (from tomorrow to Sunday)," Fina said.

The governing body had said last month that the Turin meet did not meet its rule requirements.

AGENCE FRANCE-PRESSE, REUTERS