Spain’s Prime Minister Mariano Rajoy has again reiterated his opposition to a 2017 referendum by pro-independence groups in Catalonia.
The law, he said, made it abundantly plain that such a move was unconstitutional and illegal.
The last vote in September 2014 was held as a symbolic gesture after Spain’s Constitutional Court ruled it illegal.
But Carles Puigdemont, the Catalan president, has pledged to go ahead with the referendum.
The Catalans, he said, would decide their own future by a vote that was “legal and binding”.
Mr Rajoy said he would offer dialogue on a whole range of issues, but it was not possible to hold a referendum that would “do away with national sovereignty and the equality of Spaniards.”
A number of the Catalan officials who presided over the 2014 vote have since faced trial or sanctions for their part in supporting the measure. Any vote would be expected to take place in September 2017.