Spain’s Vice President Soraya Sáenz de Santamaría said the security forces under the control of the central government did not use disproportionate force in their attempts to prevent the vote.
The referendum has been branded an “illegal” vote by the conservative Madrid administration as as the north east region attempts to break away.
Video footage shows protestors being fired with rubber bullets and police stamping on independence supporters at one polling station.
Eyewitnesses have filmed Spanish police charging at referendum voters and hitting people with batons.
One video showed a woman being thrown down a flight of stairs by riot police at one polling station.
Ms Santamaría said “actions were taken against electoral material, never against people.”
She added the actions of the forces were done “with proportionality” and in the name of “coexistence and democracy.”
Ms Santamaría claimed the referendum “did not meet the minimum democratic norms.”
During the press conference in Madrid she also launched an attack on the Catalan President Carles Puigdemont, Vice President Oriol Junqueras and Speaker of the regional Parliament Carme Forcadell.
Ms Santamaría claimed all three were responsible for organising the referendum and had behaved with “absolute irresponsibility.”
Her comments come after a number of eyewitnesses shared images and video of what would appear to be strong-arm tactics by Spain’s security forces, in particular the Guardia Civil.
The Catalan authorities have put the latest total of people injured by the likes of the paramilitary force at 465.
The Catalan government declared the Spanish government will have to answer to the international courts.
Catalan Government spokesman Jordi Turull said: “The Spanish state has been very compromised and will end up responding to the international courts.”
Mr Turull said he believed millions of votes would be counted and, while the voting hours would not be extended, those already queuing to cast their ballot would be allowed to do so. He said he did not know when the vote count would be finalised.
The UK’s Foreign Secretary Boris Johnson said Theresa May’s Government was “worried” by the violence.
Mr Johnson said: “We are obviously worried by any violence but clearly the referendum, as I understand it, is not constitutional so a balance needs to be struck. We hope very much that things will calm down.”
International law expert Trixy Sanderson said the Spanish authorities were “in clear breach of international law, specifically a breach of international peace under Chapter VII of the UN Charter.”
“The people of Catalonia have every right to self-determination and they are holding a democratic plebiscites on this issue. For the God of Seville to be using violence against them and intimidation such as photographing people in polling stations is the sort of behaviour you expect from a banana republic not a European neighbour and someone who gets to vote on our Brexit deal.
“There should be international condemnation of this where is the foreign office? The silence is deafening.”
Chapter VII of the United Nations Charter sets out the UN Security Council’s powers to maintain peace. It allows the Council to “determine the existence of any threat to the peace, breach of the peace, or act of aggression” and to take military and nonmilitary action to “restore international peace and security”.