COLOMBO (Reuters) - Sri Lanka's chief justice has been found guilty of three charges in impeachment proceedings by a parliamentary panel, a government official said on Saturday, in a case which has sparked opposition protests and raised international concerns.

It was not immediately clear if Shirani Bandaranayake, Sri Lanka's first female head of the Supreme Court, has to step down effectively from now or has to wait until parliament debates the impeachment investigations in January.

"We have found her guilty of three charges out of the first five we have investigated," Nimal Siripala de Silva, minister of irrigation and a member of the impeachment panel told reporters.

Parliament Speaker Chamal Rajapaksa appointed an 11-member select committee, seven of them from the ruling party, to investigate 14 charges against Bandaranayake ranging from not disclosing her wealth to professional misconduct.

(Reporting by Ranga Sirilal; Writing by Shihar Aneez; Editing by Jeremy Laurence)