Despite a shroud of fog over the capital and snow and slush around the rest of the country, around one-third of the Baltic state's 940,000 eligible voters had made their choice by noon, three hours after polling stations had opened at 9:00 am (0700 GMT), election officials said.
"A total of 288,906 voters had cast their votes by midday, making up 32.3 percent of all eligible voters," the election commission said in a statement.
In the last parliamentary elections, in 2003 -- the year before Estonia joined the EU -- turnout at midday was 28.6 percent.
Since then, Estonia's economy has powered ahead, growing by 11.5 percent last year, and the Baltic state has earned itself a reputation as a high-tech leader.
"Things are going fine in Estonia, but people must come out and say who should govern next," 31-year-old Siim Lepik told AFP at a busy polling station in Tallinn. "Those who don't vote won't have the right to criticize the state of affairs in the next four years," he said.
Sunday's turnout figure included some 170,000 people who cast ballots in advance voting earlier this week, of which 30,275 voted from a home or office computer in the world's first national e-vote.
Internet vote under scrutiny
The Organization for Security and Cooperation in Europe (OSCE) said the Internet vote was one of the issues its team of election observers would focus on.
"We're very keen to learn how Estonia uses remote voting on the Internet in parliamentary elections, because Estonia is the first in the world to use it," OSCE spokeswoman Urdur Gunnarsdottir said.
"Also, in all OSCE countries which have significant national minorities, we look at their situation, how they can exercise their rights," she said.
Russian officials have repeatedly complained that Estonia is violating the rights of the Baltic state's large ethnic-Russian minority, the legacy of the policy of "russifying" the Baltics carried out by the Soviets during five decades of occupation.
Around seven percent of the 1.34 million people who live in Estonia still hold Russian passports, and a further nine percent have no formal nationality. Neither group if allowed to vote.
Russia watches as former Soviet state leaves past behind
Tensions between Estonia and its former ruler were ratcheted up further last month when the outgoing Estonian parliament voted to move a World War II monument to Soviet Red Army soldiers, who chased the Nazis out of the Baltics, from its place of prominence in the center of Tallinn.
But the divisive issue of relations with Russia was expected to have little impact on the election result.
Only two of the 11 parties jostling for a seat in parliament campaigned on an ethnic Russian ticket, and analysts gave them long odds on getting into the single-chamber legislature.
"They are too marginal and not seen as trustworthy, even by the Russians," political scientist Toonis Saarts of Tallinn University said.
Polling stations are due to close at 8:00 pm CET, with preliminary results expected around midnight.
Incumbent coalition on course to retain power
A survey by the Emor polling agency published on the eve of Sunday's vote suggested that the two main partners in the ruling coalition -- the Center Party of Economy and Communications Minister Edgar Savisaar and Prime Minister Andrus Ansip's Reform Party -- would each garner 26 percent of the vote.
If they do manage to get those scores, they would be the first sitting government to be returned to power, and would enjoy between them a comfortable majority in the 101-strong single-chamber parliament.