Sweden votes in election amid heated debate on immigration

Polls have opened in Sweden's general election in what is expected to be one of the most unpredictable and thrilling races in the Scandinavian country for decades amid heated debate on immigration.

Sunday's election will be Sweden's first since the government in 2015 allowed 163,000 migrants into the country of 10 million. While far less than what Germany took in that year, it was the most per capita of any European nation. It's highly unlikely that any single party will get a majority, or 175 seats.

The latest opinion poll suggests that Prime Minister Stefan Lofven's ruling Social Democrats will substantially lose seats but still emerge a winner with an estimated 24.9 per cent of the votes.

The polls showed far-right, anti-immigration Sweden Democrats would get 19.1 per cent of the votes.