Government spokesman Keheliya Rambukwella said the papers to impeach Chief Justice Shirani Bandaranayake were handed to the speaker of the parliament on Thursday.
Rambukwella did not specify the charges against Bandaranayake but said the proposal has received the approval of more than 75 lawmakers as required.
The move comes as the government of President Mahinda Rajapaksa has been accused of tightening control over the media, police and elections officials, while carrying out political vendettas against opposition parties.
The government changed the constitution last year, giving the president power to appoint the chief justice, police chief and the elections commissioner, which is seen as a way to curb their independence.
The dispute also coincides with Sri Lanka’s periodical review at the United Nations where the country’s human rights record will be discussed.
Lawmaker Pavithra Wanniarachi, who was among those handing the motion to the speaker, said the charges against Bandaranayake include “misuse of office and personal misconduct.” She did not elaborate.
The main opposition United National Party condemned the move, saying it was a way to frighten the judiciary.
“We are against any interference made to the judiciary or any attempt to make the judiciary a political tool,” said lawmaker Tissa Attanayake, the party’s general secretary.
But he said the UNP will participate in the proceedings of the Parliament Select Committee, which will be appointed to probe the charges against Chief Justice, to ensure that it is not one-sided.
The speaker now must decide if there is a valid case against the chief justice, and then call for a vote following a debate. The impeachment motion requires more than half, or at least 113 votes, in parliament to be carried.
The government controls two-thirds of the 225-member parliament, so the motion is expected to be carried.
The impeachment motion follows months of power struggles between the judiciary and parliament. It also follows a recent Supreme Court determination that a government bill contradicted the constitution because it could take back power to the national government from provincial governments, such as for rural development plans.
And last month, a top judge heading the Judicial Services Commission was attacked by an unknown group after he said publicly that the judiciary was being pressured by powerful people and that judges were living in fear of their lives.
Opposition parties blamed the government for the attack on Majula Tillakaratne but the government has denied involvement.