Protesting students from all over the country plan to occupy the Parliament building in Sofia, demanding the resignation of the socialist-led government.
Students from Plovdiv-based universities, as cited by Darik radio, vowed they would head for Sofia on Monday evening and called on citizens to support them.
The "occupy" event is to start at 10:30 am on Tuesday.
Bulgarians have demanded the collective resignation of the Cabinet led by Prime Minister Plamen Oresharski for over 150 days.
The protests were triggered by the appointment of controversial media mogul Delyan Peevski as Chair of the State Agency for National security (DANS) in June.
The rallies were given a fresh boost as students staged full and partial blockades at a number of universities, with the central building Sofia University "St. Kliment Ohridski" inaccessible for students, lecturers, and administrative staff as of Monday.
The first point on the agenda of Tuesday's Parliament sitting is the appointment of a Deputy Parliament Speaker to replace Hristo Biserov.
Boyko Borisov, former Prime Minister and current leader of center-right party GERB (Citizens for European Development of Bulgaria), said that GERB MPs would not register for voting at Tuesday's sitting.
Biserov, who is currently being investigated for money laundering and tax fraud, resigned from the post of Deputy Parliament Speaker and Deputy Chair of liberal party Movement for Rights and Freedoms (DPS).
Borisov insisted that GERB would not take part in an election furthering the interests of backstage politics until DPS came up with a clear statement on Biserov's case.