An appeal by showjumper Denis Lynch to the Court of Arbitration for sport over his exclusion from Team Ireland for the Olympic Games has been dismissed.
The court said that it does not have jurisdiction to rule on the matter.
Denis Lynch was dropped after his horse Lantinus tested positive for hypersensitivity at the Nations Cup event in Aachen three weeks ago.
Horse Sport Ireland chief Damian McDonald has previously explained why the decision was taken to replace Denis Lynch in the Irish Olympic team.
After his disqualification Damian McDonald said that "his horse was found to be hypersensitive which can be naturally occurring and there was no finding of wrong doing against Denis Lynch out of that."
Mr McDonald said that "unfortunately, two other horses ridden by Denis in the past 12 months have tested positive for hypersensitivity, and that meant this was the third incidence of hypersensitivity."
Empty seats investigated
Meanwhile, games organisers said they are investigating why scores of seats were empty at some events yesterday.
Many people have been frustrated by their inability to buy tickets for the games, and some expressed their exasperation at seeing images of empty rows at some venues.
Olympic organiser LOCOG said it believed the empty seats were those assigned to sponsors and was investigating why they had not been used.
British Culture Secretary Jeremy Hunt said the empty seats were "very disappointing" and suggested they could be offered to members of the public.
He added: "I was at the Beijing Games, in 2008, and one of the lessons that we took away from that, is that full stadia create the best atmosphere, it's best for the athletes, it's more fun for the spectators, it's been an absolute priority.
"Locog are doing a full investigation into what happened, I think it was accredited seats that belonged to sponsors, but if they're not going to turn up, we want those tickets to be available for members of the public, because that creates the best atmosphere.
"We are looking at this very urgently at the moment."
He said a system had been introduced for these Olympics similar to the one used at Wimbledon, where people coming out of the stadium handed on their tickets so the seats could be made available to other people.
"So we are trying a lot of innovations, it's a shame this happened, but we are going to do everything we can to make sure we fill up these stadia."
Gaps in the seating were visible at the swimming, gymnastics, handball, volleyball, badminton and basketball arenas yesterday.
16 people have been arrested in London since Friday for illegal reselling of Olympics tickets.
The arrests were made on Friday and Saturday in the Stratford area near the Olympic Park in east London, and in Wimbledon, where the tennis contests are taking place.
Police said they had charged two of those arrested with ticket touting, a 57-year-old German man and a 30-year old Slovakian woman.
"Ticket touting is illegal and is a clear exploitation of those who genuinely wish to experience the Games first-hand," said Detective Superintendent Nick Downing, the officer in charge of a crackdown on illegal ticket resellers.