Indonesian authorities on Tuesday continued their search for at least 94 passengers who reportedly went missing after the boat they were traveling on sank in Lake Toba on Sumatra island, official sources said.

Head of the Regional Disaster Management Agency (BPBD) for North Sumatra, Riadil Lubis, told EFE that the accident occurred late Monday while it was covering a six-kilometer (3.7-mile) stretch between Tigaras locality and Samosir island.

"Due to bad weather and high waves, the ferry lost control. We suspect (the accident) was due to the breaking of the rudder," Lubis said.

The National Police said in a statement that at least 113 people were on board the vessel instead of some 80 estimated initially, according to a list of survivors and missing people drawn up by their families.

Rescue operations had to be halted two hours after the accident owing to bad weather and could only be resumed on Tuesday morning.

The authorities were unable to determine the exact number of passengers missing as it is common practice for boats to be overloaded.

Lubis said emergency teams were battling high waves and strong winds but has boosted efforts to try and wrap up the search by morning as heavy rainfall was expected in the afternoon.

Last week, at least 16 people died when another boat sank near the southern coast of Celebes island in the central region of the archipelago.

Indonesia records more accidents during the holiday period following the month of Ramadan when millions of people travel around the country putting pressure on the precarious infrastructure.

Ferries are a major means of transport in the Indonesian archipelago, that comprises more than 17,000 islands, and are often overloaded much beyond capacity with passenger and goods.