HELSINKI (Reuters) – Finland may usher in its first leftist prime minister in two decades in parliamentary elections on Sunday, as voters worry over the future of the country’s generous welfare system as the costs of caring for a rapidly ageing population rise. But if opinions polls are correct, the left-leaning Social Democrats’ ability to govern may be hampered, however, by a surge in support for the Finns Party, a nationalist group riding a wave of anti-immigrant sentiment sweeping the Nordics. A survey commissioned by public broadcaster Yle showed the Social Democrats could win the top spot with 19 percent of the vote, giving their leader, Antti Rinne, the first shot at forming a government. The Finns are running close second with 16.3 percent support, after scoring rapid gains since the start of this year when a series of cases of sexual abuse of minors by foreign men emerged. With the European Parliament election less than two months away, the Finnish ballot is being watched in Brussels. A strong result for the Finns Party could bolster a nationalist bloc threatening to shake up EU policy-making. Underscoring the growing confidence among far-right politicians in Europe, anti-immigration parties have announced plans to join forces following the May 26 EU election, in a move that could give them major say in how the continent is run. Just as the Social Democrats are benefiting from a growing sense of insecurity among Finland’s older and poorer voters, the Finns argue that the nation has gone too far in addressing issues such as climate change and migration at its own expense. “We are going through a cultural shock in Finland. Part of the population is in a kind of state of shock amid all the change going on, and as a result they take the Finns Party’s hand,” said Karina Jutila, chief researcher at think tank e2. Polling stations open at 9 a.m. (0600 GMT) on Sunday and close at 8 p.m. Public broadcaster Yle will give its first estimate of the results, based on advance votes which account for 36.1 percent of the electorate this year, shortly after voting ends. The success of Finland’s Social Democrats would mark a departure not only for Finland but also elsewhere in the region, where leftist parties have struggled in recent years, yielding some of their hold on the working class vote as anti-immigration nationalists of various stripes emerge. In neighbouring Sweden, Prime Minister Stefan Lofven has precariously clung to power after his Social Democrats suffered their worst parliamentary election result in more than a century last autumn. To do so, he had to enlist the support of two liberal parties with a pledge to enact a string of far-reaching right-wing policies. In Denmark, which holds an election in June, the Social Democrats are gaining ground, in part after espousing the populists’ anti-immigrant rethoric. Rinne calls his party’s immigration stance “the middle way”, favouring work-related immigration to compensate for Finland’s ageing population, but he also favours allowing some refugees in on humanitarian grounds, as the country has done thus far. The 56-year-old former union leader is also promising to raise taxes to fund welfare and combat economic inequality, which he says has risen under the ruling centre-right coalition of prime minister Juha Sipila. His talk of raising taxes is unlikely to drive off his supporters, many of whom value highly Finland’s huge welfare state. But he will likely struggle to form a functioning coalition, if the Finns score high and with Finance Minister Petteri Orpo’s National Coalition, likely to win third place on Sunday, calling Rinne’s economic policies “irresponsible”. Rinne has ruled out forming a government with the nationalists led by Jussi Halla-aho, 47, an anti-immigration hardliner. Altogether 19 parties are running in the election, with eight of them holding seats in the parliament now, ranging from the environmentalist Green party polled at 12.2 percent to the tiny Feminist Party founded just two years ago.