Ian Thorpe has criticised FINA for its ruling on transgender athletes ©Getty Images

Australia's most successful male Olympian Ian Thorpe has criticised the International Swimming Federation (FINA) for its ruling on transgender athletes which in effect prevents them from competing in women's events.

In June of this year, members at the FINA Extraordinary Congress voted to require individuals to have completed transition by the age of 12 to compete in women's competitions.

Following the effective ban, FINA also said it will establish an open category trans women would be able to compete in.

"This is a very complicated issue, I can't deny that, and I am personally opposed to the position FINA has taken on this," the five-time Olympic champion said, as reported by 1 News.

"I am for fairness in sport, but I'm also for equality in sport.

"And in this instance, they've actually got it wrong."

After retiring from competitive swimming in 2012, the 40-year-old has been an advocate for LGBTQ+ rights.

In February, he criticised Australia's new Religious Discrimination Bill, calling it "state-sanctioned discrimination".

Critics of the legislation say it enables people of faith to freely discriminate against the LGBTQ+ community.

FINA ruled that transgender individuals had to have completed their transition by the age of 12 to compete in women's competitions ©Getty Images
FINA ruled that transgender individuals had to have completed their transition by the age of 12 to compete in women's competitions ©Getty Images

Thorpe described FINA's decision as a "temporary solution" that failed to consider the implications it could have.

"When it comes to the elite level, there needs to be a sensible conversation which includes endocrinologists, psychologists, physiologists - everyone that actually may have an opinion in this space," said Thorpe, per 1 News.

"If someone is complaining about someone who is trans when they happen to be 10 years of age, it is bizarre.

"I can almost promise you that child will not be competing at an adult stage."

Thorpe has called for the protection of the transgender community, who he referred to as "some of the most marginalised and disadvantaged people" in Australia.

FINA is not alone in its ruling as other international governing bodies have passed similar laws.

International Rugby League banned transgender women this year but has vowed to do further research on its inclusion policy.

World Rugby, rugby union's global governing body, also banned transgender players from women's competitions.

The International Cycling Union lowered its limit on testosterone levels for trans women and increased the transition period, limiting opportunities.

FIFA and World Athletics also confirmed that they will review their eligibility policies.