Earlier this month, the Parliament suspended Basescu, who has been in power since 2004, amid allegations he illegally meddled in fair government policies, Voice of America reported.
Basescu leads a moderate conservative party and has been a target of the moderate liberal Social-Liberal Union in recent months, the report said.
The president has repeatedly denied allegations he exceeded his authority, undermined the rule of law and meddled in government affairs, Russia's RIA Novosti news agency reported.
However, Basescu is facing the potential of impeachment before his term ends in 2014, depending on Sunday's vote.
Under the country's constitution, more than 50 percent of voters must call for his removal and impeachment, or Basescu will retain his leadership.