According to Al-Alam news network, a court in Manama on Tuesday said the trial has been adjourned until May 7.
The decision was announced as the area where the court is located was under tight security.
The court had earlier set March 14 as the date to issue its ruling on Sheikh Qassim’s case.
The senior cleric was stripped of his nationality last June over accusations that he used his position to serve foreign interests and promote sectarianism and violence.
The clergyman, who is in his mid-70s, has denied the allegations, refused to be assigned a lawyer and declined to attend any of the trial sessions.
On Monday, people held mass protests in more than 50 Bahraini villages, among them Qassim's hometown, Diraz.
The rallies came after Bahraini clerics released a joint statement and called on all fellow citizens to show their solidarity with the cleric, stressing that the people's unwavering support for him is the "religious duty” of all Muslims.