Tanzanian authorities have arrested two church leaders for allegedly detaining dozens of sick people while promising to heal them through prayer and traditional herbs.

More than 100 people were being kept in so-called traditional wards (mud-walled huts with brick beds) built around the church in Nyamhinza village, Misungwi district, in the north-western region of Mwanza – with no medical treatment or food being provided.

Some had been there for up to a month and they were required to find food for themselves until they fully recovered.

They were found after locals alerted the police that some people were dying after leaving hospitals, including a woman who had joined the church soon after giving birth to twins.

At the end of last week, the police took the sick people back to hospitals for treatment. They are now investigating possible deaths and whether there are bodies buried nearby.

Mwanza regional police commander, Wilbroad Mutafungwa, told journalists on Wednesday that initial investigations didn't show there were people buried there but they were still keeping a close watch.

He confirmed the arrests of the suspects, church leaders William Masum and his wife Kabula Lushika, saying they didn’t have permits to conduct worship and prayer activities, or to provide traditional healing services. They have not commented on the accusations.

"We are now doing a detailed investigation, including interrogating the suspects. Meanwhile I ask locals with classified information that will help the investigation to come forward and talk to the police,'' he said.

The church is said to have been in operation for more than five years.