Brazil's Supreme Court on Wednesday rejected a petition from President Dilma Rousseff's government lawyers to halt impeachment proceedings against her, as the Senate debated suspending her from office and putting her on trial.

Justice Teori Zavascki "denied the petition to issue a stay suspending the process," a court spokesman told AFP, a decision that all but erases the leftist leader's hopes of avoiding a six-month suspension and trial in a Senate vote expected early Thursday.