The Government, after talks with lawyers, decided to change track and appeal Muralitharan's case before the sport's world governing body, Prime Minister Mahinda Rajapakse's spokesman Rohan Weliwita said on Monday.
"Even though lawyers felt there was sufficient grounds to sue, the first step will be to present an appeal on behalf of Muralitharan," said Weliwita.
"The Prime Minister is getting the support of Bangladesh, India and Pakistan in this."
Rajapakse last week met with India's top envoy in Sri Lanka, Nirupam Sen, who pledged to secure India's co-operation to defend the off-spinner who this month became Test cricket's leading bowler with 527 wickets.
The ICC has said that Muralitharan faces an year-long ban if he continued to bowl the 'doosra' -- a delivery that spins away from right-handed batsmen -- because of the unorthodox action with which he bowled the delivery.
The state-run Daily News reported on Monday that two teams of lawyers from Britain and Australia were joining their Sri Lankan counterparts to mount pressure on the ICC over the Murali issue, but Weliwita said he was unaware of it.
The Sri Lankan PM had last week brushed aside ICC chief Ehsan Mani's advice to stay out of the Muralitharan controversy and allow the ICC to deal with the situation.
Australian Prime Minister John Howard's remarks that he believed Muralitharan was a chucker, or bowled with a bent arm, had prompted the world record holder to consider boycotting Sri Lanka's tour of Australia in July.
Rajapakse reacted to Howard's remarks by announcing his intention to sue the ICC, but Mani dismissed the threat, saying there was no basis for anyone taking legal action.
"I don't know how we'd be sued, but all our regulations are fully supported by all our members," said Mani, referring to the fact that the Sri Lanka Cricket (SLC) is part of the ICC.