Mani said current levels of tolerance were set without scientific research
International Cricket Council president Ehsan Mani has defended the ruling body's proposed new throwing rule, saying it should make the game fairer.
The ICC's executive board will this month approve a plan which allows all players to bowl with an arm bent at 15 degrees from the elbow.
"What we are trying to do is to come to a system which is fair," Mani said.
"Which we can protect in the sense that once we put the criteria in place no-one can breach it."
The proposal, recommended by the ICC's cricket committee following a biomechanical study, has caused some controversy.
Under the new laws, Sri Lanka off-spinner Muttiah Muralitharan would be allowed to bowl his doosra, which was measured with a 14-degree flexion of the arm when it was banned earlier this year.
Murali hit back at allegations the rule was proposed with him in mind by accusing three prominent Australian Test bowlers of chucking.
Asked about Muralitharan, who has been reported twice for throwing, Mani said: "His action is so quick that the speed at which his arm comes down is quicker than most fast bowlers."
Mani said current limits - five degrees for spinners,
7.5 for medium-pacers and 10 for fast bowlers - had been set without any scientific research.
"We realised that some slow bowlers' arm actions were as quick as those of fast bowlers, so the question arose whether to treat them as fast bowlers or spinners.
"Instead of getting involved in that sort of discussion, we thought it better to have same level for everyone.
"So we are sending the whole proposal back to the MCC bowling review sub-committee, headed by former England captain Tony Lewis, to get their feedback on how relevant is the law that we are proposing now."