Catalan leaders have warned of civil disobedience and have said they are confident all officials, including police, would defy attempts by the Spanish government to enforce direct rule on the region.
The Spanish government has invoked special constitutional powers to fire the regional government and force a new election to counter an independence drive that has rattled the economy.
A vote in the Senate to implement direct rule is due on Friday, but the leaders of the secessionist campaign said a disputed referendum gave them the mandate to claim independence from the rest of Spain.
"It's not that we will refuse [orders]. It is not a personal decision. It is a seven million-person decision," Catalonia's foreign affairs chief Raul Romeva told the BBC.
Mr Romeva was asked whether he believed all institutions, including the police, would follow orders from Catalan institutions rather than from the Spanish government.
"From that perspective, I have no doubt that all civil servants in Catalonia will keep following the instructions provided by the elected and legitimate institutions that we have right now in place (in Catalonia)," he said.
Catalan authorities said about 90% of those who took part in the referendum on 1 October voted for independence.
But only 43% of the electorate and one-in-three Catalans participated, with most opponents of secession staying at home.
Civil disobedience was also backed by far-left party CUP, a key support for Catalonia's pro-independence minority government in the regional parliament, which called Madrid's actions an aggression against all Catalans.
"An aggression which will be met with massive civil disobedience," the CUP said in a statement.
Several hundred Catalan municipalities said they were against direct rule from Madrid and asked the Catalan parliament to vote on a motion rejecting it.
The Catalan crisis has raised fears among European countries that it could spill over to the rest of the continent.
At a European summit last week, leaders sought to minimise Spain's crisis with Catalonia and described the secession bid as a domestic issue.
Catalan president Carles Puigdemont has called the Catalan parliament to meet this week to agree on a response to Madrid, something many observers said could pave the way for a formal declaration of independence.
The Catalan parliament is to meet on Thursday morning to agree on a response to the Spanish government's decision to impose direct rule on the region.
It is the first time since Spain's return to democracy that the central government has used its powers to seize control of a regional administration.
Yesterday Spain's foreign minister denied his government's plan to impose direct rule on the region amounted to a political coup d'etat.
Several influential Catalan newspapers have called on Mr Puidgemont to resolve the crisis by calling a snap election before direct rule becomes effective. However, Catalan government spokesman Jordi Turull said this was not an option.
It is not clear whether a vote in the region would help resolve the crisis.
An opinion poll published by the El Periodico newspaper on Sunday showed a snap election would probably have results similar to the last ballot, in 2015, when a coalition of pro-independence parties formed a minority government.
Spain's Deputy Prime Minister said Mr Puigdemont would be out of a job once direct rule was enforced and Madrid would install its own representative.
The Spanish government has said it would call a regional election within six months.
"They are president of the regional government and senior figures in that government because of the constitution," said Soraya Saenz de Santamaria during a radio interview.
"They are not entrusted with that role by any divine authority," she said.
