"It would be unrealistic to ban Murali's 'doosra' delivery without the benifit of proper research having been undertaken into normal spin bowlers," former Western Australian coach Daryl Foster said in the report, published by India's The Hindu newspaper on Thursday.
Foster was part of a four-member team that tested Muralitharan's bowling action early this month after the Sri Lankan was reported for his 'doosra', a delivery which spins away from right-handers instead of coming into them.
The Sri Lankan off-spinner went to Australia for scientific tests after being reported by English match-referee Chris Broad in the third and final Test against Australia in Colombo last month.
Muralitharan, 32, is now just seven victims short of breaking retired West Indies paceman Courtney Walsh's world record of 519 Test wickets, a feat he is set to achieve in next month's two-Test series in Zimbabwe.
The tests were conducted at the Biomechanics Laboratory of the School of Human Movement and Exercise Science in Western Australia by a team comprising Professor Bruce Elliott, Jacque Alderson, Siobhan Reid and Foster.
"A straightening of 10 degrees when he (Murali) bowls his 'doosra' is not excessive and that should not therefore be deemed advantagous," Foster said in the report which is in two parts -- Bowling and Remediation.
The experts said Muralitharan initially straightened his arm 14 degrees while bowling the 'doosra' during tests, which was nine degrees more than what is permissble for spinners under the International Cricket Council (ICC) guidelines.
The tolerance limits set by the ICC are five degrees for spinners, 7.5 for medium-pace bowlers and 10 for pacemen.
Muralitharan was tested again a week later after going through a remediation process, straightening his arm 10.2 degrees this time which was still five more than what is permitted.
The report recommended that Muralitharan's level of acceptability be set at the 10-degree mark because of the speed of his upper arm rotation as it is not believed to give the Sri Lankan an "unfair advantage over batsmen or other bowlers".
"We contend that because the speed of his upper arm rotation is as fast, and in some cases quicker than fast bowlers, his level of acceptability for elbow extension should also be set at the 10-degree mark," it said.
"A case can certainly be made for some spin bowlers such as Muralitharan to have the same range of acceptability in elbow angle to that of fast bowlers. With no spin bowling data base to make a comparison, this would seem both a wise and prudent recommendation."
The ICC, however, has already said it will not relax its stipulated tolerance levels.
The report also questioned the ICC's tolerance figures, querying why 10 degrees of extension was acceptable for pacemen and only five for a spinner whose arm speed was similar.
"Without knowing what the situation is with other spin bowlers, it would seem unrealistic to ban Murali's 'doosra' without the benefit of proper research having been undertaken into 'normal' spin bowlers.
"Other off-spin bowlers, in particular Harbhajan Singh (India), Saqlain Mushtaq and Shoaib Malik (both Pakistan), all bowl the 'doosra' delivery which suggests for comparison purposes their 'other one' should also be analysed," he said.
Foster was all praise for Muralitharan, saying the Sri Lankan knew his "body and technique" very well and was able to adjust to the technical changes easily.
"In conclusion, Murali, who has been tested more than any other bowler in the history of the game -- 1995, 1999 and now -- possesses different physical characteristics which make him a unique bowler."