BANGKOK, Sept 27 (Reuters) - Increased betting on tennis is putting the sport at risk of match-fixing, according to former world number two Tommy Haas, and the German wants players and officials to keep it at bay.
"You hear stories and you wonder why we aren't watching out for these guys at tournaments," Haas told Reuters.
"There have been cases where it's quite obvious. We've had meetings about gambling... those who do it shouldn't get away with it."
A rare tennis scandal surfaced last month after internet betting firm Betfair voided bets on an ATP match in Poland between world number four Nikolay Davydenko and Martin Vassalo Arguello of Argentina after it noticed unusual betting patterns, with more than $7 million wagered on the match.
Davydenko, 70 places above the Argentine in the rankings, won the first set, but odds on the Russian suddenly drifted as all the money was placed on Arguello.
Davydenko, who retired injured with the match level at one set all, denies any involvement.
Etienne de Villiers, the executive chairman of the ATP, says the sport does not have a serious gambling problem, despite an article by French sports daily L'Equipe, which quoted two high-ranked anonymous players as saying they had witnessed thrown matches.
One player quoted in the article also estimated 60-80 percent of coaches were regularly visiting internet betting sites.
Haas, 29, said it was "probably not too difficult" to throw a game, and added that many players on the tour knew match-fixers were targeting the sport, but who they were remained a mystery.
"I've not experienced any of this but I've heard about it from other players. It's the obvious countries that we have to watch out for," he said, without elaborating.
"But we don't hear much about the problems so if they (investigators) can't find anything, we have to give players the benefit of the doubt, because we don't yet know who is behind it."
Haas is currently playing in the Thailand Open and is now one of the favourites after the ill-fated tournament was hit by a wave of 11th-hour withdrawals.
Seeds Andy Roddick of the United States, Spaniard Rafael Nadal and Novak Djorkovic of Serbia have pulled out through injury, as has Asian number one Lee Hyung-taik of South Korea, Swedes Joachim Johansson and Thomas Johansson and home favourite Paradorn Srichaphan.