An overpass collapsed in the Brazilian World Cup host city of Belo Horizonte killing at least two people and injuring 19 more, an emergency official said.

Television images showed part of a passenger bus crushed under the overpass and news website G1 said another two trucks and a vehicle were also smashed.

The accident site is around 3km from the Mineirao stadium, where a World Cup semi-final match will be held next Tuesday. The stadium has already hosted five games.

Two people were killed and 19 injured, the health agency of the state of Minas Gerais said, up from an earlier toll of one dead and ten hurt.

A firefighters' spokesman said 13 people were rescued from the bus unscathed, but the woman driver was killed.

A car was also crushed, but it was not known how many people were inside and what their condition was, firefighter spokesman Edgard Estevo da Silva told reporters.

"The vehicle is completely under the overpass," he said.

The overpass was one of the many infrastructure projects aimed at improving the city's ailing public transport network.

The bridge was to be used for passenger buses in a system known as BRT/Move, considered a legacy project from the World Cup.

Heavy government spending on the World Cup and long delays in finishing promised infrastructure projects have spurred violent street protests in Brazil over the past year, although they have died down in recent weeks.