Tim Henman has raised concerns about the problems of betting in tennis. The former British number one, who retired at the weekend, says he has heard of players being asked to influence the outcome of matches.

Henman said: "I personally have never experienced it but, listening to the players talking, it seems it goes on. We've got to be very careful, very vigilant about it as tennis doesn't want to be associated with that.

Nikolay Davydenkoo, the world number four, will be questioned by the ATP next month after the governing body launched an investigation in August, following reports of irregular gambling patterns surrounding his defeat by Martin Vassallo Arguello.

Davydenko has denied any involvement.

"There has been some pretty serious accusations in the tennis world and I, for one, will be interested to see what comes out of it," Henman added. "No-one has ever approached me. I obviously wasn't the right material.

"It (tennis) is an easy target because it's a two-horse race and there is a lot going on. You talk about a Grand Slam - there are 64 men's matches and 64 women's matches from the first round and there is a lot that can be bet on."

Roger Draper, the Lawn Tennis Association chief executive, echoed Henman's sentiments, saying: "I think we would be looking at the world through rose-tinted spectacles if we thought it didn't go on. I think the way it's going it's becoming as big an issue in sport as doping.

"I think most of the sports are hooked on to it. Sport is the second fastest growing sector of the economy at the moment - and the biggest growth area is betting.

"So we have to keep our eyes open, our ears to the ground and work with the betting companies rather than just ignore the problem and think it's going to go away. It isn't going to go away."

Henman has asked the tennis authorities to come dwon hard on players if they are found to have been involved in betting irregularities.

"We have to be sure from a player's point of view that anyone who is involved shouldn't be allowed back in the game for good," he said.