COLOMBO: Sri Lanka's anti-graft authority arrested former first lady Shiranthi Rajapaksa on Wednesday over allegations that her charity misused donations collected for a children's hospital, dealing a major blow to the once powerful family.

President Anura Kumara Dissanayake's government has revived long-dormant graft investigations involving members of the once-powerful Rajapaksa family, which dominated Sri Lankan politics for nearly two decades.

The 73-year-old wife of former president Mahinda was remanded in custody until Tuesday by a Colombo magistrate.

She was arrested earlier in the day by the Commission to Investigate Allegations of Bribery or Corruption (CIABOC) which questioned her for nearly seven hours.