Sri Lankan Prime Minister Mahinda Rajapakse on Sunday announced mounting a legal challenge against the International Cricket Council (ICC) for its decision to outlaw Muttiah Muralitharan's controversial 'doosra'.

Rajapakse said he will give leadership to defend the star off spinner and urged the entire country to rally around efforts to protect Muralitharan whom he described as a national asset.

"The Prime Minister has decided to take legal steps against the ICC for banning (Muralitharan's) doosra," a statement from his office said. "The Prime Minister is already in consultation with a team of lawyers."

The Premier said Muralitharan, the top Test wicket-taker of all time with 523 wickets, was a national asset and he will do everything within his power and that of the government to defend the bowler.

Muralitharan, whose unorthodox action has seen him being no-balled thrice in his 14-year long career, was told last  week that he could face a year long ban if he persisted with bowling the doosra, a delivery that turns away from the right-handed batsman.

ICC Match Referee Chris Broad reported Muralitharan during the Australian series in March, saying the bowler's action while delivering the doosra was suspect.

A biomechanics' report, instituted as per the ICC guidelines to deal with illegal actions, found that Muralitharan straightened his elbow by 14 degrees, which was well above the permissible five degrees, while bowling the doosra.

The report, however, mentioned that other off spinners too flexed their arm beyond the ICC tolerance levels and suggested relaxing the 'degree of flexion' so as to make Muralitharan's doosra legal.