Climate concerns top the agenda as polling stations opened in Denmark Wednesday for a general election in which the opposition Social Democrats are tipped to return to power after adopting the right wing's long-standing restrictive stance on immigration.

Opinion polls put the opposition center-left Social Democrats, led by Mette Frederiksen, at 27.2 percent, a comfortable lead of almost 10 points ahead of Prime Minister Lars Lokke Rasmussen's ruling Liberal Party, which has been in power for 14 of the last 18 years.

"Many voters want change. In particular, the 'millennials,' who can vote for the first time," said Flemming Juul Christiansen, a political scientist at Roskilde University.

Some 57 percent of Danes think the next government should prioritize climate change, according to a Gallup poll published in February. For those aged between 18 and 35, the figure was 69 percent.

Denmark's Socialist People's Party, heavily focused on environmental issues, is also expected to see a surge in its numbers, with opinion polls suggesting it could take 8.3 percent of votes, almost double its 2015 score.

If the Social Democrats emerge victorious, they intend to form a minority government - common in Denmark's proportional representation system - relying on the support of the left or the right on a case-by-case basis to pass legislation.

As Denmark enjoys robust growth, almost full employment and strong public finances, the party has focused its campaign on climate issues and the defense of the welfare state, promising to reverse budget cuts to education and healthcare.

Analysts believe the Social Democrats would likely cooperate with the right on immigration and with the left on other matters in the Scandinavian country, which is a member of the European Union but not the eurozone.

However, with a splintered political landscape featuring an abundance of political parties, the party could also find it necessary to forge long-term alliances to ensure stability. 

While the Liberal Party was expected to lose its grip on power, its performance was projected to match that of the 2015 election.

But opinion polls indicate the far-right Danish People's Party, which has informally supported Rasmussen's minority government, could lose almost half of its support, shrinking to 10.7 percent.