Brazil football star Ronaldo has come out in support of disgraced Olympic champion Michael Phelps, who was banned for three months yesterday after a published photograph showed him using a marijuana pipe.

Ronaldo, the former Barcelona, Real Madrid, AC Milan and Inter striker, sympathised with Phelps.

"There is no need to persecute someone, who has faced up to what he has done, having been at the Olympic Games and who has won almost everything that he can in his career," the footballer told reporters here.

Ronaldo himself was the centre of controversy last year when he was caught in a drugs and sex scandal with three transvestites in Rio de Janeiro.

Phelps was thrust into a media maelstrom last weekend when a picture in British tabloid The News of the World showed the winner of eight Olympic gold medals in Beijing using what looked like a glass bong typically used to smoke marijuana.

"It is clear that all sportsmen must set young people a good example, but what will he be remembered for, winning all his competitions at an Olympic Games?" said Ronaldo who was voted world player of the year three times.

USA Swimming banned Phelps for three months on Friday, but stressed the punishment was not for a doping violation, but to send a "strong message" him about his status as a role model.

The 23-year-old swimmer told his hometown newspaper the Baltimore Sun that the incident showed "obviously bad judgment and it's something I'm not proud of at all."