SOFIA - Bulgarian voters head to the polling stations on Sunday for the sixth snap parliamentary election in three years, but analysts see little chance of it producing a stable coalition that can put an end to a prolonged period of political instability.

Bulgaria has been plagued by revolving-door governments since anti-graft protests in 2020 helped topple a coalition led by the centre-right GERB party.

President Rumen Radev has had to appoint five caretaker governments since 2020 to steer the Black Sea nation as successive, inconclusive elections have thrown up unstable coalitions that have swiftly collapsed in acrimony.

Bulgaria sorely needs a period of stable, well-functioning government to accelerate the flow of EU funds into its creaking infrastructure and to nudge it towards joining the euro and fully participating in Europe's open-border Schengen area

Bulgaria sorely needs a period of stable, well-functioning government to accelerate the flow of EU funds into its creaking infrastructure and to nudge it towards joining the euro and fully participating in Europe's open-border Schengen area.

Plans to join the eurozone have already been pushed back twice because of missed inflation targets.

Bulgaria and its northern neighbor Romania removed passport checks on March 31 for people departing for or arriving from the Schengen area - including most other EU member states - by air and sea but road and rail travellers still face checks.

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Apathy is one of the main challenges in Sunday's election, when Bulgarian voters will also be choosing their representatives for the European Parliament.

Sunday's election was triggered by the collapse in March of a coalition comprising GERB, which had held power for much of the previous 15 years, and the relatively new, reformist We Continue the Change (PP) party

Sunday's election was triggered by the collapse in March of a coalition comprising GERB, which had held power for much of the previous 15 years, and the relatively new, reformist We Continue the Change (PP) party.

The two parties, both strongly pro-EU but divided by personal rivalries and distrust, said in March they could not form a new government without another election.

A poll released on Thursday by the Sofia-based Alpha Research pollster showed GERB leading with 25.1 percent and PP on 15.4 percent. The Revival party was seen getting 15.2 percent and the Movement for Rights and Freedom, which mainly represents Bulgaria's large ethnic Turkish minority, on 14.8 percent.

In a tight race, smaller parties - which include the once-mighty Bulgarian Socialist Party and an alliance of agrarian and conservative parties called Blue Bulgaria - could influence the composition of the next government.

READ MORE: Bulgaria gears up for its fifth election in two years on April 2

Mario Bikarski, a senior Eastern and Central Europe Analyst at risk intelligence company Verisk Maplecroft, said another snap parliamentary election in the autumn was probable.

"Even if a government is formed, it will likely struggle to serve a full term given ... disagreements between the various political forces," he said.