Lithuanians are voting in national elections, two weeks after austerity-weary voters evicted a centre-right coalition in the first round of a general election.
Left wing and populist opposition parties were on course to form the next government provided they win the run-off ballot which opened at 05:00 GMT on Sunday.
Lithuania's 3.3 million inhabitants face an unemployment rate of 13 per cent and declining living standards, as well as high energy costs since the country closed its Soviet-era nuclear power plant in 2009.
With just 73 of the seats in Lithuania's 141-member parliament having been won in the first round, the run-off is crucial for a trio of parties as they seek to raise their clout within the likely coalition.
Two centre left parties, the Labour Party and the Social Democrats, finished first and second in the first round, while the governing Conservatives, unpopular for cutting pensions and public wages had come third.
Labour's first-round tally was 18 and the Social Democrats' 16, while the populist Order and Justice earned six, making a total of 40, meaning they may need to bring a fourth ally on board to hit the minimum majority of 71.
Immediately after the first round, the two left-leaning parties launched talks on forming a coalition with the Order and Justice party.
But they have yet to strike a formal deal, pending the results of Sunday's ballot.
Lithuania's parties have struggled repeatedly to form stable coalitions in the two decades since the republic seceded from the Soviet Union.
The Conservatives under Andrius Kubilius who have been in power since 2008, garnered 13 seats in the first round. The tally of their governing allies from the Liberal Movement was seven.
Kubilius' government brought in a series of draconian austerity measures much wider in scope than measures adopted in western members of the European Union, which Lithuania joined in 2004.
The economy initially shrank by 14.8 per cent before growth returned in 2010, at 1.4 per cent, before hitting six per cent in 2011.
However, the upturn failed to woo voters, too few of whom felt the benefits of recovery and the pace slowed to a forecast 2.5 per cent this year.