(Adds details from ruling, currency weakens)
By Ricardo Brito
BRASILIA, Sept 12 (Reuters) - Brazilian Supreme Court justice Roberto Barroso authorized federal prosecutors to investigate President Michel Temer in an alleged corruption case involving a decree regulating ports, according to a court document seen by Reuters on Tuesday.
The investigation is based on a wiretapped conversation of a former Temer aide, Rodrigo Rocha Loures, who allegedly discussed using his influence to shape the decree in return for bribes from a company.
In his ruling, Barroso said the investigation was warranted because Brazil's top prosecutor Rodrigo Janot had found "strong indications" that crimes were committed based on the fact that the decree signed by Temer favored to some extent the interests of the company identified as Rodrimar SA.
The evidence came from a wiretap of Rocha Loures that was authorized by the Supreme Court as part of a plea bargain deal with the owners of the world's largest meatpacking firm JBS SA that lead to a previous corruption charge against Temer.
The Brazilian currency extended losses against the dollar on news of the new corruption investigation into Temer, whose efforts to bring the deficit under control have been lauded by investors as the best chance for Brazil's economic recovery. (Reporting by Ricardo Brito; Writing by Anthony Boadle; Editing by Brad Haynes, Daniel Flynn and David Gregorio)