By Anna Ercanbrack and Jussi Rosendahl
HELSINKI (Reuters) - Voters are tipped to oust Finland's pro-European and pro-NATO prime minister in Sunday's election and put in power an opposition coalition that may include Eurosceptic nationalists, hoping it will revive the sagging economy.
Opposition Centre Party leader Juha Sipila, who has backing of the urban middle class and rural conservatives, is expected to become prime minister of the euro zone country, succeeding Alexander Stubb of the centre-right National Coalition Party.
Sipila says he is open to including the Finns Party, formerly known as True Finns, in a coalition, even though they could complicate ties with Europe because they oppose bailouts and want to kick Greece out of the euro zone.
Stubb, who favors NATO membership for Finland, has led a quarrelsome left-right coalition widely blamed for failing to revive the economy and curb public debt growth after three years of recession.
The economy has been hit by weak private consumption and turbulence in neighboring Russia, a major trading partner.
According to the finance ministry, the Finnish economy is expected to grow just 0.5 percent in 2015. The new coalition is seen cutting public spending and carrying out difficult structural reforms to rein in debt.
On Thursday, an opinion poll by public broadcaster YLE showed the Centre Party leading with around 24 percent of the vote. National Coalition and The Finns scored about 17 percent each.
The centre-left Social Democrats, a partner in Stubb's government, trailed behind with around 15 percent of the votes, but more than 40 percent of those polled were undecided.
With a tradition of having majority coalitions, Finland's next government will probably include the Centre Party and two of the three runners-up. But the election is likely to open up several possible combinations, which means government talks could last several weeks.
"These elections are too much about the past, not enough about future. The politicians are lacking vision and big, concrete ideas, they are merely fighting over some small short-term issues," said a programer who gave his name Erkki, after casting his vote on the cloudy morning at Helsinki center.
"The prime minister is effectively chosen already, he has not even participated into debates lately, and all the other parties are basically tailgating him."
All the major parties have pledged some type of austerity and structural reforms, with some focusing on the welfare state, others on boosting investment or cutting red tape.
The result from the preliminary votes will be published at 1700 GMT. Public broadcaster YLE will give its first result forecast at about 1800 GMT and final results are likely after 2000 GMT.
(Editing by Alister Doyle and Raissa Kasolowsky)