
Ms Rousseff’s lawyers alleged the process is fraught with bias and irregularities but similar attempts have been rejected by the court.
Ms Rousseff could be suspended for up to 180 days if the Senators vote for a full trial today.
Earlier, her supporters set up burning barricades and blocked roads. The roadblocks caused widespread disruption across all Brazilian states.
The President is accused of illegally manipulating finances to hide a growing public deficit ahead of her re-election in 2014.
She denies all the charges.