Murray has been one of many players advocating more blood tests or the possible introduction of the "biological passport" method, which seven time Tour de France winner Lance Armstrong claimed deterred him from using performance-enhancing drugs further.

"A lot of it, unfortunately, comes down to money," said the 25-year-old Scotsman.

"Maybe it's down to the ATP (Associatom of Tennis Professionals) to invest some of our own money to make sure we get more testing done.

"If it means taking some of the money out of the players' earnings then that's what we have to do because not just tennis, all sports need to look very closely at this stuff."

The International Tennis Federation (ITF) announced last month that they are "looking very, very closely" at introducing the "biological passport" method, which takes various samples of a competitors biological data and looks for abnormalities in normal biological levels in order to spot doping, as opposed to testing for individual substances.

Figures show that the ITF conducted just 21 blood tests out-of-competition in 2011, a figure that must be improved, according to Dr Stuart Miller, head of the ITF's science and technical department.

"We think we need to increase the proportion of blood testing we do under the programme and we think we could also do with tending to increase the proportion of tests we do out of competition," he said.

Murray spoke at a promotional event for the Aegon Championships at Queen's Club, London in June

Murray, speaking at a publicity event for the Aegon Championship at London's Queen's Club in June, said that improving the standards of anti-doping in tennis is vital in order to stop drug cheats prevailing.

"I think a lot has been learned from the Lance Armstrong situation and you don't want that happening ever again." he said.

"I don't want that happening for my sport because it would be terrible."

The world number three, who finished runner-up in last month's Australia Open, also admitted that he was not sure whether tennis could be classified as a "clean sport"

"I've been asked a lot lately if tennis is clean or not," he said.

"I don't know anymore how you judge whether a sport is clean.

"If one in 100 players is doping then in my eyes that isn't a clean sport."

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