Sacked Catalonia leader Carles Puigdemont and four associates have turned himself in to the Belgian police, the Brussels prosecutor's office says, following Spain's issuing of an arrest warrant.
Puigdemont is wanted by Madrid for actions related to his push for the region's secession from Spain.
Puigdemont's move on Sunday comes as two polls suggested pro-Catalonia independence parties will together take the most seats in December's regional election although they may fall just short of a majority needed to revive the secession campaign.
Parties supporting Catalonia remaining part of Spain would divide seats but garner around 54 per cent of the vote, the polls suggested.
Spanish Prime Minister Mariano Rajoy called the December 21 election after firing the previous government and imposing direct rule over the autonomous region following a unilateral declaration of independence by Catalan lawmakers on October 27.
Catalonia's statehood push has tipped Spain into its worst political crisis since its return to democracy four decades ago as surging pro-secession sentiment in the region has in turn kindled nationalism across the country.
Puigdemont travelled to Belgium shortly after Madrid took control and now faces charges for rebellion, sedition, misuse of public funds, disobedience and breach of trust relating to the secessionist campaign.
On Saturday, Puigdemont - who will lead his independence party in the election - called for a united Catalan political front in the face of the elections.
On Thursday, nine members of his sacked cabinet were ordered by Spain's High Court to be held on remand pending an investigation and potential trial.
One member of the dismissed cabinet, Santi Vila, was freed after paying bail of 50,000 euros (NZ$84,113) on Friday. The other eight could remain in custody for up to four years.
According to the GAP3 survey, 59 per cent believed legal action against Puigdemont was unjustified while 69.3 per cent said that the jailing of the Catalan politicians would give the independence cause a boost at the ballot box.
A rally in Barcelona on Sunday, attracted just a few hundred people, a long way from the hundreds of thousands to join pro-independence marches in October, many waving the regional flag and carrying protest signs.