The authorities have rescued 12 people so far, said navy spokesperson Captain Indika De Silva.
Among those rescued are three school children, reported the Colombo Page newspaper.
The cause of the accident was not immediately clear, with Captain De Silva saying that a navy search and rescue operation is under way. There are concerns that the death toll may yet increase, with the navy deploying teams from its Rapid Action Boat Squadron (RABS), Special Boat Squadron (SBS), Marines and Divers, reported the Press Trust of India.
The ferry capsized near Kurinchankerny bridge and was going from Kurinchakeni to the town of Kinniya along the country’s eastern coast and about 160 miles north-east of the capital, Colombo, the navy spokesperson said.
The bridge connecting the towns of Kurinchakeni and Kinniya was closed due to repair work, forcing the residents to use the ferry to travel, Naazik Majeed, a social activist in Kinniya, told the Associated Press.
Angry residents burned tyres and surrounded government offices on Tuesday afternoon as they blamed officials for the accident.
Additional reporting by agencies
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies