A woman prepares her ballots at a polling station in Barcelona on November 10, 2019 during a general election in Spain. Photo: VCG

Spain's Socialist Premier Pedro Sanchez emerged as winner but weakened from Sunday's repeat election that propelled the far-right Vox into third place in a ­result set to deepen years of political turmoil.

The ballot, the fourth in as many years, failed to draw a line under months of parliamentary deadlock following an inconclusive April poll which Sanchez won but left him unable to form a government.

The Socialist leader, who had called the vote to strengthen his hand, ended up losing three seats in a poll that weakened his potential allies and strengthened the right. 

The campaign has been overshadowed by the Catalan separatist crisis that has played squarely into the hands of the far-right which over the past year has made significant inroads into Spain's political arena.

Announced some four hours after polling stations closed, the final results showed the Socialists taking 120 of the parliament's 350 seats (28 percent of the votes) while Vox secured 52 (15 percent) - more than double its mandates in the outgoing assembly.

Vox only made its parliamentary debut in April when it won 24 mandates in the biggest showing by the far-right since Spain returned to democracy ­after dictator Francisco Franco's death in 1975. 

In second place was the right-wing Popular Party, which took 88 mandates (nearly 21 percent), up from 66 in the previous poll. 

Sunday's vote will only prolong the chronic political turmoil in the eurozone's fourth-largest economy, Teneo analyst Antonio Barroso told AFP. 

"The results will make forming a government more difficult due to the parliament's deep fragmentation and the rise of Vox," he said, warning that the divisions "were so problematic" that it was impossible to rule out yet another election. 

In recent days, Sanchez had ­repeatedly raised the alarm about Vox's "aggressive ultra-right wing" policies, warning the party would drag the country back to the dark days of Franco's dictatorship. 

But his warnings appeared to have fallen on deaf ears. 

Turnout dropped 2 percentage points compared with April's figure, standing at 69.87 percent.