The Spanish justice minister Rafael Catala has criticised protesters who have rallied in support of former Catalan president Artur Mas, who is standing trial in Barcelona for holding an illegal referendum on the region's secession from Spain.

"What is happening on the streets of Barcelona is inappropriate. It does not look like a democratic society," Catalan said in an interview with Spanish radio station Cope on Monday (6 February). "Democracy is respect to the institutions and what they're doing is not respecting the judiciary power," he added.

Thousands of independence supporters marched through the streets along with Mas and two of his former associates before the court appearance on Monday.

Protesters were chanting "independence, independence", "down with Spain's justice system" and "we want to vote", The Local reported.

Mas, who stepped down from his role in 2016, faces a 10-year ban from holding public office for disobedience against the state and wrongdoing as a public official. Former regional vice president Joana Ortega and education councilor Irene Rigau are facing similar charges, and they are facing fines and a nine-year disqualification from politics.

Spain sued the Catalan government in November 2014, shortly after the separatist region held a referendum on gaining independence from Madrid on 9 November. The mock referendum had been declared illegal by Spain's Constitutional Court less than a week before the vote, but Mas decided to pursue the public consultation regardless.

According to The Associated Press, the former president refused to answer questions from the prosecutors but, in reply to his own defence lawyers, he said his cabinet's aim "wasn't holding a vote that was immediately legally binding but rather knowing people's opinion after massive protests in past years." According to the referendum organisers, 80% of the 2.3 million Catalans who casted a ballot voted to secede from Spain.

Former President of the Catalan Government and leader of Partit Democrata Europeu Catala (Catalan European Democratic Party) PDECAT Artur Mas stands with members of the Catalonian government, the Catalan Parliament, Catalan mayors and party members a few moments before Mas's arrival at the TSJC (Superior Court of Catalonia) in Barcelona Josep Lago/AFP

The five-day trial is likely to reignite longstanding tensions between the central government and the pro-independence supporters in the north-eastern region of 7.5 million people. According to the Associated Press, polls show that those who want independence are a minority, albeit one gathering increasing support.

Secessionists argue the region, which accounts for around 20% of Spanish GDP, needs independence to protect their culture and their language, Catalan, which is spoken alongside Spanish.

The new regional government has pledged to continue the independence struggle, promising to pass laws to enable a legally binding referendum later in the year. "Today, many of us feel as if we're being tried," current regional head Carles Puigdemont said outside the court on Monday, as reported by Reuters.

But as Prime Minister Marian Rajoy remains steadfast in his refusal to grant an official, legal vote to the region, it is unclear how a new vote would be anything other than symbolic.