Polls ahead of the general election have shown a weakening of populist, conservative and the social-democratic parties.
Latvians head to the polls with victory expected for centrist parties that have vowed to continue backing Ukraine and beefing up national security.
Polls ahead of Saturday's general election have shown a weakening of populists, conservatives and the social-democratic party, Harmony, which usually has strong support from Latvia's large Russian-speaking minority.
Political expert Marcis Krastins said Prime Minister Krisjanis Karins was "most likely" to win, depending on how many smaller parties supporting him get past the five percent threshold for entering parliament.
"Russians invading Ukraine helps Karins to secure voters in Latvia because in such times people tend to rally around the flag," he said.
Karins's New Unity Party topped one recent opinion poll with 13.3 percent.
Harmony, which has come first in recent elections but has lacked enough allies to govern the Baltic state, got 5.1 percent.
Ahead of the election, President Egils Levits warned voters against backing politicians in the Russian-speaking community who "hesitated to state clearly who the aggressor was and who the victim was at the beginning of Russia's invasion of Ukraine".
He also criticised populist parties who "offer simple and often impractical solutions to extremely complex problems, who promise to reduce all the costs and increase all the subsidies from one day to the next".
Dominated over the centuries by Teutonic knights, Swedes, Poles, then Russians, Latvia gained independence in 1918 before finding itself under Soviet occupation in 1944-1990.
Today, the Russian-speaking minority makes up around 30 percent of the population of 1.8 million.
Polling stations opened at 0400 GMT and close at 1700 GMT.