Madrid: Spaniards on Sunday voted in rain-sodden elections that were all but certain to hand a thundering victory to the right and topple yet another debt-laden eurozone government.

Bowed by a 21.5 percent jobless rate, economic stagnation and deep spending cuts, the first voters of the 36 million-strong Spanish electorate headed to polls ready to punish the ruling Socialists.

"Spain chooses a government to confront the crisis storm," blared the front page of the leading centre-left daily El Pais. "Spain stakes its future.”

Opposition Popular Party leader Mariano Rajoy has a lead of about 15 percentage points over the Socialists, the latest polls showed, enough for an absolute majority in the Parliament and a free hand to reform.

Voters vented anger with the ruling Socialists over the economic crisis that has pushed the number of unemployed close to five million, but some were also wary of Rajoy, who has promised even deeper spending cuts.

Octavio Arginano, a retired 67-year-old factory worker, said he voted for the right for the first time in his life.

"My son has been unemployed for over a year, my daughter earns just 600 euros (USD 800) a month looking after young children," he said as he left a polling station in the Madrid neighbourhood of Lavapies.

"There has to be a change although I am not sure anyone knows what to do to get us out of this situation."

If the polls are right, Spain would become the last of the so-called periphery eurozone nations to ditch its government this year, after the debt crisis toppled rulers of Ireland, Portugal, Greece and Italy.

The ruling party's candidate, Alfredo Perez Rubalcaba, 60, cast his vote in Madrid shortly after the polls opened and urged Spaniards not to shun the polls.

"Spain is at a historic crossroads," he told reporters. "The next four years are very important for our future and in these conditions it is even more important that people vote."