By Karolos Grohmann

LAUSANNE, Switzerland (Reuters) - Banned Olympic 400 meters champion LaShawn Merritt's exclusion from the 2012 Games stands because it is the International Olympic Committee (IOC) which decides who takes part, the IOC said on Wednesday.

American Merritt was suspended for 21 months by an American Arbitration Association last year for testing positive for banned substances he said were in a male enhancement product.

Under a rule introduced in 2008 by the IOC, any athlete banned for six months or more is ruled out of the next Olympics although U.S. arbitrators have said this went against the World Anti-Doping Agency code.

"The rule stands," IOC Vice President Thomas Bach told Reuters. "The IOC has the right to put in conditions for participation. This is one of those conditions. It is not a sanction but an issue of eligibility."

"The athletes' commission made it very clear today that it is supporting this rule," said the German.


Merritt's ban, backdated to October 28, 2009, elapses in July 2011, but the IOC rule prevents him from taking part in London.

The American arbitrators said the rule goes against the WADA code and, as a signatory to the code, the IOC could not ban Merritt from the London Games.

Merritt, who is eligible to take part in the U.S. Olympic trials, is considering an appeal at the Court of Arbitration for Sport.

"I like the BOA rule and if everyone in the world would adopt it would solve so many things," Fredericks told reporters.

"It is the rule I would like to see in the world. If the rest of the would could have it, it would be nice. It would give more credibility to the Olympic champion."

A final decision on Merritt's case will affect dozens of other banned athletes still hoping to compete in London.

American swimmer Jessica Hardy is in a similar situation.

She was forced out of the 2008 Olympics after testing positive for a banned substance and would be barred from the London Games despite her two-year suspension being reduced to one.

"We will see what happens and we are interested in solving this issue as soon as possible," said Bach. "You cannot close your eyes to the argument of the other side but the IOC is governing the Olympic Games and puts conditions.

"This is the full resolve of the IOC to fight against doping and that Olympic athletes serve as role models," he said.

(Editing by Ed Osmond and Justin Palmer)