Sydney - Michael Phelps was "extremely lucky" to escape with only a three-month ban from competition for smoking marijuana, Australian Olympic champion Libby Trickett told a newspaper here on Saturday.
USA Swimming announced the suspension after a photograph in a British newspaper appeared to show multi-Olympic champion Phelps smoking marijuana.
The organisation said it wanted to send a "strong message" to the champion swimmer about his status as a role model for young people.
'Unacceptable behaviour'
But Trickett said the penalty was too lenient considering the three-month suspension won't lead to the Olympic star missing any major competition. He would also remain eligible to compete in the world championships in Rome in July.
Trickett told the Daily Telegraph: "Personally, I think he's extremely lucky and if it had fallen under anti-doping laws, the penalty could have been double and that would have cost him a spot at the worlds.
"He's got to face up to the responsibilities that come with being a role model and this is simply unacceptable behaviour from someone with his stature and profile in sport.
"He can hopefully learn from the mistake.
Learn from mistake
"It takes some of the shine off his spectacular performances in Beijing and this behaviour simply isn't okay."
Trickett won two gold medals, a silver and a bronze in Beijing in August last year.
Retired Australian Olympic and world champion Grant Hackett said Phelps would learn from his mistake.
"US swimming officials had to send a clear message and they've done that," Hackett said.