Sanna Marin
At 34, Marin is set to become the world's youngest sitting prime minister.Reuters

Finland's Social Democrats, on Sunday, elected the 34-year-old former transport minister, Sanna Marin, to the post of prime minister, making her the country's youngest head ever.

Marin, whose party is the largest in a five-member governing coalition, narrowly won to replace outgoing leader Antti Rinne, who resigned on Tuesday. Rinne had resigned after losing the confidence of the coalition partner Centre Party over his handling of a postal strike.

"We have a lot of work to do to rebuild trust," Marin told reporters after getting elected. "I have never thought about my age or gender, I think of the reasons I got into politics and those things for which we have won the trust of the electorate," she added.

World's youngest state leader

At 34, Marin is set to become the world's youngest sitting prime minister, ahead of New Zealand's Prime Minister Jacinda Ardern who is 39, and the PM of Ukraine Oleksiy Honcharuk who is 35.

Marin had also become the head of the city council of her industrial hometown of Tampere at the age of 27.

Sanna Marin
Marin had also become the head of the city council of her industrial hometown of Tampere at the age of 27.Twitter

Former PM Antti Rinne had headed Finland's centre-left five-party coalition since June, and Marin's appointment is unlikely to lead to significant policy changes by the Social Democrat-led administration.

"We have a shared government programme which we have committed to," Marin said.

The SDP won April's legislative elections on promises to end years of economic belt-tightening introduced by the Centre Party to lift Finland out of a recession.

Rinne stepped down after several weeks of political crisis over a plan to cut wages for 700 postal workers.

Finland's postal service withdrew the reform plans in November after widespread strikes, but questions emerged over whether or not Rinne had previously endorsed the cutbacks, leading to the Centre Party declaring it had lost its trust in the prime minister last Monday.

Parliament is expected to formally swear in the new prime minister on Tuesday.

(With agency inputs.)