The President of Kiribati says a ferry that has been missing for 11 days may have been carrying as many as 100 passengers.

Earlier reports had said the MV Butiraoi was carrying about 50 people from Nonouti Island to the capital Tarawa - a journey that should have taken no more than two days.

Photo: NZ Defence Force

President Taneti Maamau says the government did not become aware of the missing vessel until last Friday.

An international search began at the weekend with a New Zealand Air Force Orion on Sunday locating eight survivors drifting in a dinghy.

They have since been picked up by a fishing boat.

After a special cabinet meeting today, the President said the vessel was not seaworthy.

He also said the government had announced a national week of prayer.

Meanwhile searchers are continuing to scour more than 300,000 square kilometres of ocean for survivors.