(CNN) -- Two pro-euro candidates appeared headed for a February runoff in Finland's presidential race after a first round of voting Sunday, according to complete results.
With all boxes reporting, conservative former Finance Minister Sauli Niinisto had a solid lead with just under 37% percent of the vote. Meanwhile, pro-European Green League candidate Pekka Haavisto passed euro-skeptic Paavo Vayrynen to claim the No. 2 spot, with 18.8% over Vayrynen's 17.5%. Vayrynen had been running second in earlier returns.
Niinisto and Haavisto -- Finland's first openly gay presidential candidate, according to Finnish media -- are vying to succeed Tarja Halonen, Finland's first female president. Halonen has has reached her two-term limit after beating back a challenge from Niinisto, of the conservative National Coalition Party, in 2006.
A runoff between the top two finishers is slated for February 5. Turnout was estimated at nearly 73% of Finland's 4.4 million eligible voters. The eventual winner will break a 30-year lock on the presidency by Halonen's Social Democrats.
Finland is one of the states that joined the euro from the beginning, when Niinisto was finance minister. He insists Finland should stay in the eurozone, despite the debt crisis that has taken some of the shine off the common currency.
His NCP won the top share of votes in last April's parliamentary election, and already leads a broad coalition government that includes the Social Democrats.
Finland is one of the few remaining AAA-rated countries in the eurozone. But 2012 is only expected to deliver a growth of 0.4%, with the possibility of a new recession, its finance ministry reports.
It has had to take part in the bailouts of other euro states who faced deep financial problems, such as Greece and Ireland. Many Finns now see Niinisto -- who also served as deputy chairman of the European Investment Bank -- as someone who can stand up for Finland's interests in the single currency.
Haavisto, meanwhile, has served as Finland's environment and development minister and has international experience working for the European Union and the United Nations in Sudan and the Middle East.
Vayrynen and his Center Party have argued that Finland should leave the euro, and he insisted before Sunday's vote that polls showing him running third were wrong. His third-place showing Sunday followed a strong finish in April by the euro-skeptic True Finns Party, which won 39 seats in parliament to become the third-largest party.
The True Finns demanded that Finland stop supporting the eurozone bailouts, but its presidential candidate, Timo Soini, was running fourth in Sunday's balloting. He told Finnish public broadcaster YLE that his weak support was an indication that his party wants him to remain as party leader, rather than president.
Finland's president is in charge of the country's foreign policy, together with the government, and serves as commander-in-chief of its defense forces. But recent changes have seen more power being given to the government and parliament, and former President Mauno Koivisto told YLE that there was a risk of an "imbalance" between the direct public election of the president and the office's diminishing power.