By Jussi Rosendahl and Tuomas Forsell
JYVASKYLA, Finland (Reuters) - Finland's eurosceptic Finns party, which is part of the ruling coalition, elected an anti-immigration hardliner as chairman on Saturday in a move that analysts said might lead to a break-up of the three-party government.
At a Finns party congress, 56 percent of its members voted in favour of European Parliament member Jussi Halla-aho while 37 percent backed the more moderate Sampo Terho.
Halla-aho, who wants Finland to leave the European Union, has said he would push his centre-right coalition partners to tighten immigration policies, and would not stick to the three-party government at any cost.
"We must be more aggressive in raising the topics that distinguish us from other parties... it is important to push our priorities forward more vigorously within the government programme," Halla-aho told reporters after the vote.
However, the co-ruling pro-EU National Coalition Party (NCP) said it might not want to cooperate with Halla-aho who was fined by Finland's Supreme Court in 2012 for comments on a blog that linked Islam to paedophilia and Somalis to theft.
"This (leader change) requires serious consideration. The Finns party is not the same party anymore," Finance Minister Petteri Orpo told Verkkouutiset, an online news site close to his NCP party, but did not comment further.
As snap elections are very rare in the Nordic country, a possible break-up of the coalition would likely mean that Prime Minister Juha Sipila from the Centre Party would try to form a new coalition from the current parliament.
That could derail healthcare and local government reforms central to Sipila's plan to balance public finances.
Sipila, who has yet to comment on the government's future, is due to meet Halla-aho and Orpo on Monday.
The Finns party has rural roots but Halla-aho is expected to lead it towards a more hardline right-wing populism. Formerly known as True Finns, the party is known for complicating EU bailout talks during the euro zone crisis.
After becoming the second-biggest party in parliament, it softened its nationalist and anti-EU stance but support for Finns plunged from 17.7 percent in a 2015 election to about 9 percent in a poll this month.
Mari K Niemi, a researcher at University of Turku, said the government may break up due to the change.
"The image costs to NCP for cooperating with the Finns party led by Halla-aho may be quite considerable."
"NCP joined the coalition with a populist party that partly sought to represent underprivileged people in the rural side. That party is now becoming a more radical right-wing populist party with a focus on criticising immigration."
Finland is recovering from a decade of stagnation and problems including the decline of Nokia's former phone business. The government has sought to boost growth and curb public debt growth by cutting spending and reforming labour laws.
Outgoing Finns Party leader and co-founder Timo Soini stepped down after 20 years. It was unclear whether he will continue as the country's foreign minister.
(Editing by David Clarke and Alexander Smith)