"It's difficult to prove if someone has tanked a match or not tried because they can try their best until the last couple of games of each set and then make some mistakes, a couple of double faults, and that's it."
Former British player Barry Cowan said he was aware of low profile professionals being vulnerable to fixing attempts, the Guardian reported.
"I know it goes on, that players are approached. It goes on at ATP and Challenger level where if you lose in the first round you only get $225," Cowan said.
Former British number one and TV pundit Andrew Castle criticised Murray for going public with his claims, rather than taking what he knows to authorities.
"I think he has been unguarded and naive...tennis has been thrown into something that doesn't make the game look good."
But Castle is "very concerned".
"We don't know whether it's male or female, we don't know whether it was singles, doubles or mixed...there are different categories and it does worry me," he said.
He believed to top of the game was clean, but elsewhere "we might have a bit of a problem that needs to be looked at."
"But nothing's being suppressed...I have complete faith in the governing body," he said.
A former British Davis Cup player Arvind Parmar is among players to claim he was offered money to throw matches. Worldwide sports betting is worth trillions of dollars and the European Gaming and Betting Association says tennis is second to football as the most active market.