At least 41 people were killed and dozens injured when a bus and a truck collided on a busy road in south-west Tanzania on Wednesday, police said, warning that the death toll could rise.

Officers said many died when a container that was being ferried on the truck fell on the bus after impact, crushing the victims on a highway in Iringa, about 460 km (276 miles) south-west of the commercial capital Dar es Salaam.

"The accident occurred when a passenger bus carrying more than 60 passengers crashed head-on with a container truck," Iringa police chief, Ramadhani Mungi, told Reuters by telephone from the scene of the accident.

"The container on the truck fell on the bus and crushed the passengers. Survivors of the accident have been rushed to hospital for emergency medical attention."

At least 23 people were injured, some of them seriously, raising concerns that the death toll could rise, police said.

Traffic accidents are common in east Africa's second-biggest economy, where buses are the main form of public transport between towns and roads are often poor. Critics blame authorities of failing to enforce basic traffic regulations, while police say many of the accidents are caused by speeding.