Sri Lanka's former first lady Shiranthi Rajapaksa has been arrested over allegations that a charity she is linked to misused donations raised for a children's hospital.

Anti-corruption authorities arrested the 73-year-old wife of former President Mahinda Rajapaksa at their Colombo home on Wednesday.

They are questioning her over the 10 million rupees ($30,300; £22,800) of donations collected by the Siriliya Saviya charity, meant to be spent on a specialised scanner for Colombo's Lady Ridgeway Children's Hospital.

But officials say such a scanner had already been donated by the Chinese government.

Shiranthi Rajapaksa has denied any wrongdoing and says the money has not been appropriated.

She returned to Sri Lanka on Monday from Singapore, where she was receiving medical treatment. She had filed a court petition to try to prevent her arrest, but the hearing was set for 12 October.

Ex-President Mahinda Rajapaksa's spokesperson, Manoj Gamage, has said the money is safe in Siriliya's accounts and that no fraud has occurred.

Mahinda Rajapaksa served as president of Sri Lanka from 2005 to 2015 and for years, his family held a tight grip over the country's politics. He was hailed by many as a hero for bringing an end to nearly three decades of civil war when Tamil Tiger rebels were crushed in 2009, during his first term as president.

But in 2022, protests broke out across the country as inflation surged and Sri Lanka ran out of fuel, food and medicine.

Mahinda's brother Gotabaya Rajapaksa, who was serving as leader at that time, was eventually toppled.

Sri Lanka's current government, under President Anura Kumara Dissanayake, has since revived long-stalled corruption investigations involving various members of the Rajapaksa family.

Mahinda and Shiranthi's eldest son, Namal Rajapaksa, was arrested earlier this year over allegations linked to an aircraft procurement deal made during his father's presidency. He is currently held in remand.

His brother Yoshitha was also arrested earlier this year on corruption charges.