The 41-year-old Kiviniemi, minister for public administration and local government, is set to replace Prime Minister Matti Vanhanen, who announced in December he would not run for re-election as head of the party.

She beat Economic Affairs Minister and veteran Centre politician Mauri Pekkarinen in a second round of voting at a party congress, winning 57 percent of the vote.

If, as expected, she is approved as prime minister by parliament, she faces a tough challenge.

The Centre's popularity has fallen due to a 2009 party funding scandal that also touched other parties. A recent poll showed the party well behind the co-ruling Conservatives and main opposition Social Democrats.

Kiviniemi will also have to nurture Finland's ailing export-dependent economy back to health. Gross domestic product (GDP) plummeted 7.8 percent in 2009, although modest growth of 1.1 percent is expected for this year.

The next parliamentary elections are due in April 2011.

Kiviniemi is set to take the reins of the government before the end of June, with the 4-party coalition government to temporarily step down before reforming.

Vanhanen, prime minister since 2003, will step aside on June 18. He decided not to seek re-election because of leg surgery that will require a long convalescence.

Anneli Jaatteenmaki, Finland's first female prime minister, resigned only three months after the 2003 parliamentary elections due to a leaked Iraq war document scandal.