The governor of Brazil's Central Bank, Henrique Meirelles, has strongly denied any wrongdoing in his financial affairs and insisted he will not resign.
Mr Meirelles said his financial secrecy had been violated
Mr Meirelles urged police to investigate how details of his banking records were leaked to the media.
He said he had the full support of President Luiz Inacio Lula da Silva.
A news magazine has alleged that Mr Meirelles moved $50,000 from an undeclared US bank account to one held by a firm of Brazilian money-changers.
The report on Thursday in Veja magazine said the firm of dealers was being investigated for money-laundering.
It followed separate press allegations that Mr Meirelles had filed contradictory tax returns.
All the claims refer to the period before Mr Meirelles, a former top executive at FleetBoston Financial Corporation, took up his current post.
Responding to the allegations, Mr Meirelles told Brazil's Globo television: "I am giving no thought to the possibility of resignation.
"I continue to enjoy the support of the president and of Finance Minister Antonio Palocci."
He added: "Some people are committing a crime of violating financial secrecy, taking confidential information and spreading bits of it in a distorted form to confuse public opinion."
Mr Meirelles has already said he made proper tax declarations before and after moving back to Brazil from the United States in 2002.
He has also denied all knowledge of the firm of money dealers.