|Silva is accused of arranging up to $23m in kickbacks from government contracts to benefit himself [EPA]
Brazil's sports minister is under pressure to quit as more evidence emerges of wrongdoing at his ministry.
Orlando Silva is accused of arranging up to 40m reais ($23m) in kickbacks from government contracts to benefit himself and the Communist Party, which is part of the government of Dilma Rousseff, the Brazilian president.
Silva faced calls to resign on Tuesday, with newspapers saying that remaining in office would undermine his authority and create turmoil for Rousseff.
"The minister must leave," the Estado de Sao Paulo newspaper said in an editorial on Tuesday.
The accusation has deepened doubts about Brazil's preparations to host the next World Cup. The scandal is particularly embarrassing for Brazil as it hopes to use the 2014 World Cup and the 2016 Olympics later to showcase its emergence as an economic power.
The influential news magazine Veja reported during the weekend that Silva headed a scheme dating back to 2004 in which 20 per cent kickbacks were charged on public contracts, including sports projects for needy children
Silva has denied any wrongdoing, but he looked increasingly vulnerable as details emerged of sloppy bookkeeping and favouritism in the sports ministry's contracts with non-governmental organisations.
Silva was due to testify on the matter in congress on Tuesday.
Citing local media reports, a government watchdog, known by its Portuguese acronym CGU, said 59 contracts signed by the sports ministry between 2006 and 2011 did not comply with regulations.
It has demanded that contractors return 24.5m reais.
The scandals had appeared to be abating before the Veja report on Silva, but have resurfaced, exposing deep rifts in the disparate ruling coalition and delayed Rousseff's legislative agenda.
The construction of stadiums and airport terminals for the World Cup and Olympics has been delayed and Silva's departure could throw preparations into further disarray.
Even if Silva is not directly linked to corruption, he may ultimately be held accountable for poor oversight.
"Silva's arguments will be put to the test in coming days," Folha de Sao Paulo newspaper said in an editorial on Tuesday.
"But at the head of a portfolio full of suspect deals, his political vulnerability is evident," Folha added.
Rousseff, on a weeklong tour of Africa, has only given half-hearted support to Silva, who was deputy sports minister under her predecessor, Luiz Inacio Lula da Silva.
She said he was innocent until proven guilty but also acknowledged shortcomings in the oversight of contracts with NGOs.
"It looks increasingly difficult for him to hang on to his job," said Jose Luciano Dias, a Brasilia-based political consultant.