Ousted Catalan leader Carles Puigdemont has called for a united political front in the December 21 election to continue the drive for independence from Spain and to protest against the imprisonment of former members of the regional government.
Mr Puigdemont, who went to Belgium after his government was fired following a unilateral declaration of independence, said on Friday he was considering standing in the election from Brussels.
In Spain's gravest political crisis since the return of democracy in the late 1970s, Prime Minister Mariano Rajoy called the snap election after taking control of Catalonia a week ago.
Political parties that wish to run on a common platform have until Tuesday to register any potential coalition and until November 18 to put forward their candidates.
"It is time for all democrats to join together. For Catalonia, for the freedom of political prisoners and for the republic,"Mr Puigdemont said in a tweet that included the hashtag for llistaunitaria.cat, a site calling for parties to unite against the Spanish government at the ballot box.
Signatures on the website rose to more than 40,000 from just 2000 within a few hours of Mr Puigdemont's tweet.
The wealthy northeastern region continues to be evenly split between those that support leaving Spain and those that wish to remain part of the country, according to polls taken since the declaration of independence.
Mr Puigdemont has said he would not return to Spain until he has been given unspecified "guarantees" by the Spanish government. Following the warrant, any extradition process could take 45 days, though this could be extended up to 90 days.
Mr Puigdemont reiterated on Saturday in a tweet that he would fully co-operate with Belgian justice following the warrant.
Asked if he would detain Mr Puigdemont on Saturday, Belgian prosecutor Eric Van Der Sypt said it was unlikely.
"Tomorrow, or it could be possible on Monday," he said.
"We are not in a hurry. He said he would collaborate. We don't have any reason to believe he will flee. We are going to do this thoroughly."
While anti-independence parties urged Catalans to go out and vote in the December election, the arrests helped fuel the antagonism felt by many in the region toward the central government in Madrid.