Finland's Prime Minister Sanna Marin, set to leave office after losing a general election, announced Wednesday that she and her husband have filed for divorce.

"We have filed for divorce together. We are grateful for the 19 years together," Marin said in an Instagram story.

She added that she is "still best friends" with her partner Markus Raikkonen, who shared the announcement on his own Instagram profile.

The pair have a five-year-old daughter and Marin said that "we will continue to spend time together as a family".

In April, Marin's Social Democrats fell to third place with 43 seats in the 200-member parliament, behind the conservative National Coalition with 48 seats and the anti-immigration Finns Party with 46.

The National Coalition is currently negotiating to form a government with the Finns Party.

The now 37-year-old Marin became the world's youngest elected head of government in 2019, running a centre-left coalition with five women party leaders, four under the age of 35.

From steering her country into NATO to headlines about partying, Sanna Marin was Finland's most popular prime minister in decades but nonetheless proved a polarising figure.

Her popularity peaked during the Covid-19 pandemic, building her reputation as an unwavering crisis leader.

But she was soon entangled in headlines relating to her private life, polarising her reputation.

In August 2022, leaked social media videos showing Marin partying with a group of Finnish celebrities made news around the world, prompting her to take a drug test to clear suspicions of wrongdoing.

While some defended her right to a private life, to others the scandals were not fit for her office and evidence of her inexperience.

Marin's government has formally resigned but will continue serving on a caretaker basis until the formation and appointment of a new government. 

ehu/pvh