SOFIA - Bulgarians voted Sunday in a close snap general election marred by accusations of vote-rigging and expected to result in a political stalemate and fresh protests in the EU's poorest member.

Despite its ouster by mass protests just three months ago, the conservative party of former bodyguard ex-premier Boyko Borisov, promising stability and infrastructure development, was tipped to win the most votes.

Polls gave his GERB 29-35 percent, well short of a majority, although it would mark the first time since the end of communism that the same party comes first in two consecutive general elections.

The socialist BSP party, pledging more jobs and fairer taxes, was predicted to come in a close second with 25-32 percent, with some surveys suggesting a neck-and-neck race or even a surprise last-minute victory.

But the discovery on Saturday of 350,000 illegal ballot papers at a printing firm whose owner is reportedly close to GERB cast a shadow over the polls.

The head of the socialists, Sergey Stanishev, openly accused GERB of preparing for "total falsification of the elections" as analysts predicted people would again take to the streets.

Anger over grinding poverty and shattered prospects six years after EU accession sent thousands onto the streets this winter, but the mood turned to disillusionment and apathy during the electoral campaign.

Mudslinging over a recent wiretapping scandal also diverted attention from ordinary people's concerns in a country where almost a quarter of the population lives below the official poverty line.

Six people have died since February after setting themselves on fire in protest or despair over poverty and corruption.

Whichever party wins the election will face the tough task of finding at least two coalition partners in a severely fragmented parliament.

These could include the ultra-nationalist Ataka party, the Turkish minority party MRF and potential kingmaker DBG, a new centrist party formed by ex-European commissioner Meglena Kuneva.

A hung parliament could spell months of political deadlock, while a potential failure to form a government could trigger new snap elections in the autumn.

A possible political crisis would only add to the economic woes of Bulgaria, which mustered just 0.8 percent growth last year. Foreign investment in the country has fallen and unofficially almost one in five is jobless.

President Rosen Plevneliev called for people to come out and vote, but only around half of Bulgaria's 6.9 million voters were expected to cast ballots in the election for the 240-seat parliament.