Muttiah Muralidharan in action during a game of American football, part of Sri Lanka’s practice session in Bulawayo on Wednesday. The second ODI against Zimbabwe is on Thursday. (Reuters)

London: Sri Lankan off-spinner Muttiah Muralidharan could be banned for up to 12 months if he continues to bowl his doosra because his action exceeds official guidelines, the ICC said late on Tuesday.

Muralidharan underwent tests on his action at the University of Western Australia after being reported by Match Referee Chris Broad during the Sri Lanka-Australia series last month.

Sources privy to his assessment said bio-mechanics experts believe Muralidharan should be allowed to bowl his doosra, a delivery that turns in the opposite direction to his normal off-break, even though his arm straightens by about ten degrees.

Sri Lanka board chief Mohan de Silva said after the University report arrived that he was “confident Murali will be able to continue bowling that delivery.”

However, the ICC stressed that “the existing regulations governing the degree to which a spin bowler can straighten his arm or ‘level of tolerance’ (five degrees) remain in place and will be enforced.

“...Should any bowler be reported for a second time within 12 months of the first report, the ICC will convene a hearing of its own Bowling Review Group which has the power to impose a ban of up to 12 months should it determine the bowler’s action is illegal.”

Muralidharan, who has taken 513 Test wickets, is on the verge of overtaking West Indies’ Courtney Walsh (519) to become the game’s leading wicket-taker. He is expected to achieve the record in the series against Zimbabwe this month, edging ahead of Australia’s Shane Warne (517) on the way.

The 31-year-old bowled in front of 12 cameras at the University with his body strapped in reflective markers so a computer could track his action.

The ICC confirmed that at this stage of the process “any decision or action arising from the report will be the responsibility of Sri Lanka Cricket.

“This includes any decision on whether or not the bowler should continue to bowl the particular delivery that has been the subject of the investigation.”

But an ICC spokesman said that if Muralidharan’s doosra exceeds the ‘level of tolerance’ guidelines, which sources said it does, he faces a ban if he continues to bowl it.

The ICC regulations state that pace bowlers are allowed ten degrees of flex, medium-pacers 7.5 and spinners five.

The University has suggested that further research needs to be undertaken to ascertain whether the levels are practical.

“In most bowlers it (the straightening) is more than five degrees and we don’t know on what basis the ICC arrived at this,” Mohan de Silva said last week.

ICC chief executive Malcolm Speed, responding to media coverage of the alleged contents of the University report, clarified the background to the levels of tolerance saying:

“(They) reflect the reality that most bowlers straighten their arm to some degree when bowling. These current levels of tolerance are based on expert advice that suggests beyond a certain level, bowlers will gain an unfair advantage...

“As recently as last September at its meeting of Board Chief Executives, the ICC reviewed these levels and all countries were in agreement that the current standards should remain in place.

“There has been some media speculation that because the ICC will be conducting further research into the actions of spinners, the current levels of tolerance should not be applied in this (Muralidharan’s) case. This suggestion lacks common sense.”