The session is in response to the Spanish government invoking Article 155 of the Spanish constitution allowing the central government to intervene in running Catalonia, after the region voted in favour of independence in a banned October referendum.
Catalonia's regional parliament will hold a plenary meeting on Thursday, a lawmaker with the ruling Catalan separatist coalition said on Monday.
Many fear the session will become a cover for a vote on declaring independence from Spain.
Catalan President Carles Puigdemont has asked the parliament to convene a debate and vote on how to respond to the central Spanish government's plan, announced over the weekend, to take direct control of the northeastern region.
Puigdemont's speech on Saturday was seen as a veiled threat of formalising an ambiguous declaration of independence earlier this month that he declared suspended in order to earn time for negotiations.
The Spanish government says no dialogue is possible with independence on the table and is manoeuvring to sack all the Catalan top officials and call a snap regional election in the next six months.
Lluis Corominas, the Junts pel Si (Together for Yes) spokesman in the regional parliament, said the proposal for holding the plenary on Thursday was backed by the far-left separatist allies of the CUP party.
Spanish Prime Minister Mariano Rajoy announced on Saturday he was seeking to trigger Article 155 of the Spanish constitution allowing the central government to intervene in running Catalonia, after the region voted in favour of independence from Spain in a banned October 1 referendum.
Rajoy's move was met with anger and shock in Catalonia.
Corominas accused Spain of acting "like a dictatorship" and called the use of Article 155 "an act of institutional violence without precedent."
"In this parliament we won't be able to debate or vote any initiative without Madrid's permission," the lawmaker said. "That is not democracy."
The CUP issued an announcement on Monday morning calling for "mass civil disobedience."
The party described Rajoy's move as "the greatest aggression against the civil, individual and collective rights of the Catalan people" since the dictatorship of General Francisco Franco, who died in 1975.
The party said it would be met by civil disobedience as a form of non-violent resistance. It said it would elaborate on what form of action this would take later in the week.