Prosecutors in Belgium's capital, Brussels, said they were examining the arrest warrants for Puigdemont and four of his associates Saturday and hope to launch extradition proceedings as soon as possible.
"We will study it, we will give it to an investigative judge maybe tomorrow or the day after tomorrow", Van der Sypt told Reuters.
The Belgian public prosecutor's office confirmed Saturday that it had received the warrants, saying a decision would happen within 24 hours of them appearing before a judge. He also said that the snap election will not "be neutral, independent, normal", if the Catalan leadership is in jail.
Mr Puigdemont and several ousted Cabinet members remain in Brussels, where he said they are seeking "safety and freedom" while judges back in Spain investigate them for pushing Catalan secession.
But the longer Mr Puigdemont can delay his arrest and extradition, the greater chance he has of being a factor in the December 21 election that Spanish authorities have called as part of their temporary takeover of running the rebellious region.
While Puigdemont and his four aides hid in Belgium, nine members of his deposed government complied with a summons to appear in a Madrid court. On Thursday, ex-Catalan Vice President Oriol Junqueras and seven other former regional ministers were jailed without the opportunity to post bail.
"If (Spain) wants democratic elections, if it wants to show that it is really democratic, it is necessary that it releases the main leaders of one of the options that will run for elections", Republic Left general secretary Marta Rovira said.
Told of Puigdemont's unity call, the ERC's deputy leader, Marta Rovira, responded simply: "We must win (the elections) and that is what we will do".
Embroiled in Spain's gravest political crisis since the return of democracy in the late 1970s, Prime Minister Mariano Rajoy called the election when he took control of Catalonia in response to last week's declaration of independence by its parliament.
Assemblea Nacional Catalana and Omnium Cultural have spearheaded the civil society efforts to achieve secession for the northeastern region.
The 7.5 million people of Catalonia, which until this past week had considerable autonomy, are fiercely proud of their language and culture but are also deeply divided about the push for independence.