Judge Llarena set bail at 100,000 euros (£88,225) for the six other Catalan politicians who were jailed in November on preliminary charges of rebellion and other offences.
The Catalans' legal team, however, said the alleged offenses are "not punishable" under Belgian law and said their human rights would be affected if they were returned back to Spain.
Ousted Catalan president Carles Puigdemont and four former ministers are in exile in Belgium on the wake of an arrest warrant and extradition request issued by Spain.
The former Catalonia leader and four of his former ministers fled to Belgium in October, claiming they would not get a fair trial in Spain.
The early election is an attempt to find a democratic way out of the nation's worst crisis in almost four decades.
This means that until December 21, the deposed president of Catalonia, a candidate in the election, will lead an atypical election campaign from Belgium. But the vote is shaping up as a plebiscite between those for and against independence, with polls predicting a close race between the two camps.
After Monday's hearing the court is expected to make its ruling in eight to 10 days, according to the Brussels prosecutor's office.
Campaigning for the election, with Junqueras at the head of the list for his ERC party, begins on Tuesday.
Junqueras and the other jailed politicians pledged last week to give up on efforts to seek unilateral independence for the wealthy northeastern region, in the hope of being freed.
Magistrate Pablo Llarena ordered ousted Catalan Vice President Oriol Junqueras, the former regional interior minister Joaquim Forn and the leaders of two Catalan separatist groups to remain in jail without bail.
In a court statement, the judge ruled that, while he considered there was no risk the defendants would leave the country, he did believe there was a risk of criminal reiteration.