Spain will seek to suspend Catalonia's autonomy unless the region's leader abandons his push for independence, the country's deputy prime minister said Wednesday, 24 hours before Madrid's deadline.

If separatist leader Carles Puigdemont does not provide a satisfactory response by 0800 GMT Thursday, "Mr Puigdemont will provoke the application of article 155 of the constitution," Soraya Saenz de Santamaria told parliament.

This provision of the constitution -- which has never been used before -- would open the way for Madrid to impose direct rule over the semi-autonomous region.

Triggering it could represent a drastic escalation of Spain's worst political crisis in decades which was sparked when Catalonia held a banned independence referendum on October 1.

Meanwhile, Prime Minister Mariano Rajoy also appealed Wednesday to Catalan leader Puigdemont to "act sensibly."

"I ask Puigdemont to act sensibly, in a balanced way, to put the interest of all citizens first," Rajoy said in parliament.

Rajoy has given Puigdemont until Thursday to come up with a definitive answer on the independence question, or face the consequences.

The premier would need Senate approval to trigger article 155, but his conservative Popular Party has a majority there.

The move could ultimately allow Madrid to suspend the regional government and eventually trigger new elections for Catalonia, but such a move risks inflaming tensions in the region even further.

Puigdemont declared independence following the poll which he says resulted in a 90 percent "yes" vote, though turnout was only 43 percent as many supporters of Spanish unity stayed away in a region that is deeply divided on the issue.

But the Catalan leader said he was "suspending" independence to allow time for talks with the government -- a prospect Madrid has rejected, leaving the country in limbo.