Puigdemont, who fled to Belgium in October after the Catalan parliament declared independence, was picked as candidate to lead the region again this week after December elections saw separatist parties win an absolute majority.
But how he can do this remains a mystery as he needs to be physically present in the regional parliament to be sworn in, but faces arrest for his attempt to break from Spain as soon as he comes back to the country.
Prime Minister Mariano Rajoy plans to “challenge in the Constitutional Court the decision by the (Catalan) parliament's speaker… in which he proposes lawmaker Carles Puigdemont as candidate for the regional presidency,” Rajoy's deputy Soraya Saenz de Santamaria told reporters.
She added Rajoy had made a preliminary request to the state council, the government's advisory body, for a report into whether this was feasible before taking the matter to the court.
High alert for return
Puigdemont has said he could be sworn in remotely from Brussels, a plan Spain's central government opposes.
He said he would rather return to Spain, but without any risk of arrest.
On Wednesday, he said he should be present at the parliamentary session due next week where lawmakers will officially vote him in.
But Saenz de Santamaria said there was “an arrest warrant against Mr. Puigdemont in Spain, so the first thing he should do in Spain is go to Spanish judicial authorities.”
She added this meant he would not be able to be present at the session.
Still, Spanish authorities are on high alert for a possible return of the Catalan leader.
On Tuesday, Interior Minister Juan Ignacio Zoido said authorities were “taking steps along the border and inside the country, everywhere, to see that that does not happen.”
“We are doing it in such a way that he cannot enter (the Catalan parliament) even in the boot of a car,” he told Spanish television.
Catalonia's independence declaration on October 27 was short-lived as Rajoy moved to stop the crisis in a region deeply divided over secession.
He imposed direct rule on the semi-autonomous region, sacked its government including Puigdemont, dissolved its parliament and called snap elections.
Several days later, separatist leaders were charged for their attempt to break from Spain via a banned independence referendum, but by then Puigdemont and several of his former ministers were already in Belgium.
Deposed vice president Oriol Junqueras, however, remained in Spain and was jailed along with others pending a probe into their role in the independence drive.