Spain's ruling People's Party (PP) has suffered historic losses in regional elections to new grassroot parties after four years of severe spending cuts and a string of corruption scandals.

Exit polls showed on Sunday that although Prime Minister Mariano Rajoy's PP won the most votes in 11 of 13 regions, it is facing what could be its worst election result in more than 20 years, as an economic rebound after a severe recession failed to conserve the absolute majority it had held in most regions.

The new market-friendly Ciudadanos ("Citizens") and anti-austerity Podemos ("We Can") parties made strong gains, earning seats in almost all of the regional administrations, according to a poll by television channel Antena 3.

In a foretaste of national elections expected in November, the country's main parties will now have to enter a period of coalition and compromise in the 13 of Spain's 17 regions that voted on Sunday, alongside more than 8,000 towns and cities.

The PP is set to lose its absolute majority in regional bastions Madrid and Valencia, where potential left-wing coalitions could send the party into the opposition for the first time since the mid-1990s.

One exit poll also showed the PP losing the key stronghold of Madrid city for the first time since 1991 to a leftist platform backed by Podemos, although a second poll showed a tie between the two.

In local elections four years ago, the PP snared absolute majorities in eight regional governments, allowing it to run them without making political alliances. This time, it won none outright, the poll said. That means the PP will have to seek pacts with other parties, perhaps leaving the newcomers as power brokers.

Shift in political landscape

The exit poll results confirmed recent opinion polls that the new parties would mount a strong challenge and bring a shift in Spain's political landscape.

In the simultaneous elections for town halls, the PP and the main opposition Socialist Party - which have alternated in government for nearly four decades - won only 53 percent of the nationwide vote, the poll said. That was significantly down from the 65 percent of the vote the pair gathered in the 2011 municipal elections.

There was also an upset in Barcelona, where a popular anti-eviction campaigner backed by Podemos was poised to unseat the region's long dominant and conservative Convergence and Union party.

A 23 percent jobless rate, cuts in public services such as health and education, and political corruption scandals have fuelled the emergence of new parties offering change.

Spain isn't the first southern European country to witness a shift in the political centre of gravity since Europe's debt crisis prompted governments to slash public spending. In recent years, the traditional parties of governments in Italy and Greece have also seen their influence eroded.

Source: Agencies