A number of stadia used to host games during the 2014 Fifa World Cup in Brazil are under scrutiny amid new political corruption investigations in the country.

The Reuters news agency reports that a newly-unsealed plea-bargain testimony from engineering group Odebrecht cited irregularities at six venues that featured at the national football team tournament.

The Corinthians Arena in Sao Paulo, National Stadium in Brasilia, Pernambuco Arena in Recife, Castelao Arena in Fortaleza, Amazonia Arena (pictured) in Manaus and the Maracana stadium in Rio de Janeiro were mentioned.

Evidence released by the Supreme Court suggests that builders and politicians collaborated to fix contracts at the venues, which reinforces existing suspicions that many of the Brazil 2014 venues were overpriced.

Executives from Odebrecht gave their testimony as part of a settlement with US, Brazilian and Swiss authorities, and Reuters said at least five of the individuals confirmed payments were made to secure “an unfair advantage associated with work on the Maracana stadium”.

In addition, for the venues in Pernambuco, Manaus and Fortaleza, Odebrecht and another construction firm collaborated to “frustrate the competitive character of the bidding process”.

Politicians named in the testimony have so far denied any wrongdoing.

Last year leading Brazilian construction firm Andrade Gutierrez Engenharia admitted it was part of a cartel involved in stadia development for the 2014 World Cup.