In a press conference at lunchtime on Wednesday, Rajoy said the action from the Spanish government will depend on Catalan president Carles Puigdemont's response.
"This requirement is necessary when activating article 155 of the constitution. With it we want to offer certainty to citizens," Rajoy continued, referring to the article of Spain's constitution that would permit intervening in Catalonia's autonomy.
"If Puigdemont respects the law, it will end a period of illegality and uncertainty. That's what everyone is waiting for in order to end the situation Catalonia is experiencing," he concluded.
On Tuesday, a Spanish constitutional law expert told The Local that triggering article 155 is uncharted territory, and it may also end up doing little to deter separatists.
"The thing about article 155 is it's a very serious reaction that has never been used before and doesn't have previous legislative development to consult, so it's not really known what measures would be adopted," Joan Vintró, lawyer and lecturer on constitutional law at the University of Barcelona explained.
"It's designed to always be applied temporarily: you can't dissolve Catalan autonomy without changing the Spanish constitution. Even if elections in Catalonia are forced, you could end up back in the same place as it's entirely possible the pro-independence parties end up in the majority again."