More than 200 people are feared to have died after a ferry sunk in Tanzania's Lake Victoria, a senior local official said.

At least 44 people have already been confirmed dead, Ukerewe District Commission Colonel Lucas Magembe said.

And 37 have been rescued, John Mongella, Mwanza's commissioner said.

The rescue mission has been halted until dawn on Friday.

Another official said the vessel was overloaded and had more than 400 people on board.

However, it was difficult to establish just how many passengers there were, as the person dispensing tickets drowned with the machine recording the data.

The MV Nyerere ferry capsized just metres from the dock on the island of Ukerewe, between the islands of Ukora and Bugolora, on Thursday afternoon.

The Tanzania Electrical, Mechanical and Electronics Services Agency - which is in charge of servicing the vessels - said the ferry was involved in an accident, but gave no further details.

Spokeswoman Theresia Mwami denied there being any mechanical problems as the company had carried out heavy maintenance on the ferry in recent months, including two new engines.

Ireland's ambassador to Tanzania, Paul Sherlock, has offered his condolences to all those affected by this "terrible accident".

Poleini sana wote. This is a terrible accident. Condolences to all those affected #MvNyerere https://t.co/3hlw4fp7LA

— Paul Sherlock (@paul_sherlock) September 20, 2018

The Irish embassy in Dar es Salaam has yet to comment on the incident.