Mariano Rajoy said he had asked Catalan leader Carles Puigdemont to confirm whether or not he has declared independence.
The move is a first step towards activating Article 155 to suspend Catalonia's autonomy.
On Tuesday Mr Puigdemont signed a declaration of independence, but halted implementation to allow negotiations.
Mr Rajoy accused Mr Puigdemont of creating "deliberate confusion" and said he wanted to restore "certainty".
"This call - ahead of any of the measures that the government may adopt under Article 155 of our constitution - seeks to offer citizens the clarity and security that a question of such importance requires," Mr Rajoy said.
The man who wants to break up Spain
The view from Barcelona v Madrid
Catalonia crisis: What are the options now?
Mr Rajoy was speaking after holding an emergency cabinet meeting to discuss the government's next steps.
BBC Europe Editor Katya Adler reports that the Spanish senate has said preparations to trigger Article 155 have begun, but the legal process will not begin until a response has been received from the Catalan leadership.
Spain's prime minister is trying to put the ball back in the Catalan court by asking for clarification.
There is no official time frame for the response, although political sources and Spanish media are talking about five days.
In the meantime sources from Spain's upper house of parliament - the senate, where Mr Rajoy's PP has a majority - say the request is in to be able to trigger Article 155 to suspend Catalan autonomy
But Article 155 has never been used before and there are disagreements about how it would work in practise.
Spain has been in turmoil since a disputed referendum in Catalonia on 1 October which was declared invalid by the country's Constitutional Court.
Addressing the Catalan parliament in Barcelona on Tuesday evening, Mr Puigdemont said the autonomous region had won the right to be independent as a result of the vote.
He urged the international community to recognise Catalonia as an "independent and sovereign state".
He said the "people's will" was to break away from Madrid, but he also said he wanted to "de-escalate" the tension around the issue.
With this in mind he announced that he was "suspending the effects of the declaration of independence" for more talks with the Madrid government, which he said were needed to reach a solution.
He and other Catalan leaders then signed the declaration of independence. It is not clear if the declaration has any legal status.
Influential figures including Barcelona's mayor Ada Colau and European Council President Donald Tusk had urged Mr Puigdemont to step back from declaring independence.
Reality Check: Would Catalonia be a viable country?
Catalan crisis: Six things you need to know
Almost 90% of voters backed independence with a turnout of 43%, Catalan officials say. Anti-independence voters largely boycotted the ballot and there were several reports of irregularities.
National police were involved in violent scenes as they tried to stop the vote taking place.
Catalonia is is one of Spain's wealthiest regions, but a stream of companies has announced plans to move head offices out of Catalonia in response to the crisis.
The European Union has made clear that should Catalonia split from Spain, the region would cease to be part of the EU.
No comments: