Latvians are choosing a new parliament in an election overshadowed by the Ukraine crisis and worries over how to deal with resurgent neighbour Russia.
Analysts said the governing centre-right coalition, headed by Prime Minister Laimdota Straujuma, looked set to return to power after Saturday's election with two separate polls taken within two weeks of election day, giving the four-party bloc a clear lead.
The coalition, which has welcomed the build-up of NATO forces in the region as protection against Russia, is pitted against the opposition Harmony party.
The opposition is backed mainly by the country's Russian-speaking minority which favours balancing Latvia's Western orientation with stronger links to Moscow.
Russophones are the permanent political opposition and are likely to remain so even after the 2014 parliamentary election
Polling stations opened at 04:00 GMT and will close at 17:00 GMT on Saturday.
Russia's annexation of Crimea and meddling in the eastern Ukraine conflict have sent shudders through the country of two million people.
Ahead of the election, questions about national loyalty surfaced after police reports about a handful of ethnic-Russian Latvian citizens joining pro-Moscow rebels in eastern Ukraine.
"If Harmony ever got in, it would be a disaster for the country. They would sell it to Russia," Karlis Kalnins, a musician, told the AFP news agency in the capital Riga.
The leftist Harmony topped the 2011 snap election, but without a majority or coalition partners, it was relegated to the opposition in the 100-seat parliament.
"Since independence was regained in 1991, all Latvian governments have been composed of varying [majority]... coalitions representing ethnic Latvian interests," University of Latvia Professor Daunis Auers told AFP.
"Russophones are the permanent political opposition and are likely to remain so even after the 2014 parliamentary election."
After regaining independence in 1991 following five decades of Soviet occupation, Latvia and Baltic neighbours Lithuania and Estonia turned West, joining NATO and the European Union in 2004.