A new anti-graft party attracted more support than expected in Bulgaria's third general election this year, with some polls suggesting it had won Sunday's vote.

As the Balkan country fights its deadliest coronavirus wave, exit polls suggested We Continue the Change, led by two Harvard-educated former businessmen, had won 26 percent of the vote.

They gave three-time premier Boyko Borisov's GERB 23 percent, after initial exit polls had given him the lead. The first partial official results are due to be published Monday.

Just over 23 percent of Bulgaria's population of 6.9 million people is fully vaccinated against Covid
Just over 23 percent of Bulgaria's population of 6.9 million people is fully vaccinated against Covid AFP / Nikolay DOYCHINOV

Kiril Petkov and Assen Vassilev, who both did stints as interim ministers earlier this year, formed the movement in September, tapping into frustrations voiced in massive anti-graft protests last year.

"Bulgaria is taking a new path," Petkov, who is aiming for the prime minister's chair, said after polls closed.

"Left, centre or right, it doesn't matter," he said. "If we can stop (corruption) and redistribute money for the well-being of the taxpayers, then we should be able to come to an agreement with several parties."

Boyko Borisov, who faced massive anti-graft protests last year and multiple revelations about alleged past misuse of public funds, is seen as an "unacceptable" partner by most other parties
Boyko Borisov, who faced massive anti-graft protests last year and multiple revelations about alleged past misuse of public funds, is seen as an "unacceptable" partner by most other parties AFP / Nikolay DOYCHINOV

Earlier in the day, the 41-year-old said the country considered the EU's most corruption-prone member needed "a normal, operating government".

His movement was willing to partner with all parties who pledge to stop graft, he said.

Analysts have said they expect parties to try hard to form a government to end the country's worst political crisis since the fall of Communism, highlighting the need to tackle the raging pandemic.

With the EU's lowest Covid vaccination rate, Bulgaria now has one of the world's highest pandemic death rates as the coronavirus spread overwhelms short-staffed hospitals and fills up morgues.

Elections in April and July returned fragmented parliaments with no party able to find enough partners to form a government, leaving many voters disheartened.

An estimated 40 percent of voters turned out for the weekend poll.

"I wish the elections are successful this time so that we have a new government for a better life," pensioner Stanka Lenkova, 73, said at a polling station on the outskirts of Sofia earlier Sunday.

Just 23 percent of Bulgaria's 6.9 million people are fully vaccinated, while around 200 have been dying each day in recent weeks.

An interim administration failed to impose stricter measures and stop new infections and deaths from spiralling upward.

"These elections showed society's resolve to break with corruption and arbitrariness," Rumen Radev, who is running for a second term as president, said after polls closed.

He urged parties to form a government that is "reformist, against corruption and social".

But calls for change may not be enough -- according to experts, they may be forced to ally with the country's Socialist Party, whose image remains tainted by the disastrous transition to democracy of the 1990s.

With 49 percent of the vote in presidential elections also held Sunday, the former jet fighter pilot and air force commander is expected to easily win a run-off on November 21.

We Continue the Change seems likely to form a government "because it can build bridges between the right and the left," said analyst Ivailo Ditchev of Sofia University.

Another analyst, Boriana Dimitrova of Alpha Research, said the results showed voters' "mobility and uncertainty" in flocking to support the new party.

But she warned that Petkov and Vassilev, 44, though "very enthusiastic" had little experience in politics and might end up leading an "unstable" coalition.

Borisov's GERB party has campaigned on a promise to restore "order" amid the pandemic and as rising electricity and gas prices have hit the economy.

"We will do everything we can to end this chaos," Borisov told reporters as he cast his vote.

Anti-establishment singer Slavi Trifonov, whose party came first in July with 24 percent of the vote but then failed to form a government, got only 10 percent this time, according to exit polls.