Lance Armstrong has pulled out of a masters swimming event in Texas this weekend after the sport's governing body attempted to bar the athlete.
FINA said in a statement on Thursday that athletes convicted of doping offences were not allowed to enter competitions sanctioned by the world swimming body.
"Therefore, FINA wrote a letter to the US Masters Swimming (with copy to US Aquatic Sports and USA Swimming) requesting not to accept the entry of Mr Lance Armstrong in the above mentioned competition," it said on its website (www.fina.org).
The Austin-based American Statesman newspaper reported earlier that Armstrong, who was stripped of his seven Tour de France titles and banned for life last year after doping charges, planned to take part in the Masters South Central Zone Swimming Championships in the Texan state capital.
It quoted Rob Butcher, the executive director of masters swimming, as saying nobody had filed a grievance against Armstrong competing in an event that does not come under the umbrella of the US Anti Doping agency.
Media reports said Armstrong had been due to compete in the 500, 1,000 and 1,650 yard freestyle races in his home city.
Masters swimming is open to anyone aged over 18 and is popular with triathletes.