Voting precincts have opened in Lithuania, with opposition leftists and populists expected to vie for victory over the unpopular conservative government that took over four years ago as the Baltic country slid into a deep recession.

Lithuanians will also be asked whether their country should build a new nuclear power plant in an effort to establish energy independence after closing a Soviet-era atomic facility in 2009. Although the referendum is non-binding, a large `no' vote could torpedo plans to build the plant along with neighbors Estonia and Latvia.

Lithuania relies predominantly on Russian gas for energy, and consumers have seen their monthly energy bills soar in recent years.

Opposition Social Democrats led in most polls prior to Sunday's ballot, with a populist party led by an impeached former president trailing close behind.