A Spanish judge has jailed nine former Catalan ministers as they await questioning over charges of rebellion and sedition, as prosecutors pushed for an arrest warrant for sacked leader Carles Puigdemont.

Key points: Catalan leader Carles Puigdemont is in Brussels seeking "freedom and safety"

Catalan leader Carles Puigdemont is in Brussels seeking "freedom and safety" Several former Catalan Cabinet members remanded in custody

Several former Catalan Cabinet members remanded in custody Altogether 20 Catalan politicians are being investigated

Mr Puigdemont and his 13-member Cabinet are being investigated for their pursuit of Catalan independence after the Spanish Government removed them from office on October 27.

After the nine Catalan Cabinet members who showed up at Madrid's High Court were questioned, a judge sent eight of them to jail without bail, while one was ordered held in lieu of 50,000 euros ($76,000 in bail).

The seven men and two women were taken from the court in police vans hours later and assigned to prisons in the Madrid area.

Mr Puigdemont later described the jailing of Catalonia's former cabinet members as "a serious mistake".

Arrest warrant for Catalan leader sought

Meanwhile, prosecutors have requested the courts to issue a European arrest warrant — valid throughout all EU states — for ousted leader Mr Puigdemont, who failed to turn up at court and remains in self-imposed exile in Belgium.

A court source meanwhile told reporters that "the warrant [for Mr Puigdemont] will most likely be issued on Friday [local time]".

In all, 20 regional politicians are being investigated on possible charges of rebellion, sedition and embezzlement for a declaration of secession the Parliament of Catalonia made on October 27.

Also overnight, six Catalan politicians appeared for a parallel session in the Spain Supreme Court — they were given a week to prepare their defences and instructed to return for questioning on November 9.

The crimes are punishable by up to 30 years in prison under Spanish law.

Mr Puigdemont surfaced in Belgium on Tuesday with some of his ex-ministers, saying they were seeking "freedom and safety" there — he and four of the officials remained in Brussels on Thursday.

Mr Puigdemont's number two, former vice-president Oriol Junqueras, was the first to arrive on Thursday at the High Court.

Thousands rally in support of ousted leaders

Sorry, this video has expired Thousands of supporters gathered throughout Barcelona to greet the ousted Catalan politicians (Photo: AP/Manu Fernandez)

He went in accompanied by lawyers, passing by dozens of journalists, and declined to answer questions.

Spain took the unprecedented step of triggering constitutional powers allowing it to take over running Catalonia following the region's declaration of independence.

Madrid dismissed the Catalan Cabinet, dissolved the regional parliament and called a new regional election for December 21.

Javier Melero, a lawyer representing some of the separatist politicians investigated in the Supreme Court, criticised Mr Puigdemont and the four ministers who skipped court.

He said their actions would be damaging for his clients, three politicians who are members of Mr Puigdemont's PDeCAT party.

"Not being at the service of the judiciary when you are summoned is always damaging for the rest of those being investigated," Mr Melero said.

About two dozen politicians and elected officials from Catalan separatist parties gathered at the gates of the Supreme Court in a show of support for those under investigation.

In Barcelona, the Catalan regional capital, thousands of people rallied outside the regional presidential palace in Sant Jaume Square to show their support for the pro-secession politicians, clapping and chanting slogans in favour of independence.

The protracted political crisis over Catalonia, Spain's worst in decades, could have an impact on the country's economic growth, Spain's central bank warned in a report published on Thursday.

Spanish and Catalan separatist flags are waved in front of the Catalan regional government headquarters in Barcelona. ( Reuters: Juan Medina )

AP/Reuters