Brazil's Bar Association, journalists and opposition lawmakers have reacted with outrage to reports that the country's federal police plan to investigate the bank accounts of an American journalist who published leaked conversations between prosecutors and the graft-busting judge who is now Jair Bolsonaro's justice minister.

The rightwing site the Antagonist (O Antagonista) reported on Tuesday that federal police had asked a money-laundering unit at Brazil's finance ministry to investigate the "financial activities" of Glenn Greenwald.

Police declined to comment on the allegation but confirmed an investigation had been launched into the hacking of cellphones that led to the leaks.

"This seems to me like an attempt to intimidate the journalist," said Kennedy Alencar, a leading political commentator on CBN Radio.