VILNIUS - Lithuanians head to the polls on Sunday to decide a parliamentary election dominated by concerns over the cost of living, with the opposition Social Democrats ahead after the first-round vote.

The Baltic country of 2.9 million people has a hybrid voting system in which half of parliament is elected by popular vote. The rest is decided in district-based run-off votes between the top two candidates, a process which favors the larger parties.

Polling stations open at 7 am (0400 GMT) and close at 8 pm (1700 GMT). Results are expected at about midnight local time (2100 GMT).

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If the left-leaning Social Democrats won 20 percent of the vote in the election's first round on Oct 14, making it the largest party ahead of the ruling Homeland Union with 18 percent and the anti-establishment Nemunas Dawn with 15 percent.

Prime Minister Ingrida Simonyte's center-right three-party coalition has seen its popularity eroded by high inflation that topped 20 percent two years ago, deteriorating public services and a widening gap between rich and poor.

After the first-round vote, SD leader Vilija Blinkeviciute said she was already in talks about forming a majority coalition government with two other parties - For Lithuania, and the Farmers and Greens Union.

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The SD made a pact with opposition parties to support all run-off candidates running against Simonyte's Homeland Union nominees.

Domestic economic issues were in focus during the election campaign, with the SD vowing to tackle increased inequality by raising taxes on wealthier Lithuanians to help fund more spending on healthcare and social support.