GENEVA • The Swiss are heading to the polls on Sunday to vote in a new Parliament, with the populist right seen as likely to strengthen its already dominant position amid concerns over migrants and asylum rules.

The surging numbers of refugees moving through Europe have heightened the focus on the issue in Switzerland, even though the wealthy Alpine nation has yet to be significantly affected by the crisis.

The last poll from the gfs.bern polling institute showed that 48 per cent of those questioned thought migration was the most important issue facing the country.

Power-sharing and consensus rule are the norm in Switzerland and elections rarely lead to major shifts in Parliament or the make-up of the government, which does not directly reflect the power balance in the legislature.

But the latest polls suggest that the scale is tilting from the centre-left towards a centre-right majority in Parliament, which has 200 seats in its lower chamber and 46 in the upper chamber.

"That could clearly impact future decisions," said Mr Andreas Ladner, a political scientist at Lausanne University, suggesting a centre-right tilt in Parliament could lead to "stricter immigration policies".

About a quarter of Switzerland's eight million inhabitants are foreign nationals.

Pollster gfs.bern said the country had not seen a campaign so dominated by a single issue for decades, with only 9 per cent choosing the runner-up issue - Switzerland's relationship with the European Union - as the most important. Ties with the EU were badly hit by a narrow Swiss popular vote in February last year in favour of restricting immigration from the bloc.

Switzerland's largest party, the populist right-wing anti-immigration Swiss People's Party (SVP), appears to be benefiting from the increased focus on its pet issue, mainly at the expense of the Greens and other smaller parties.

The latest polls handed SVP nearly 28 per cent support - up from the 26.6 per cent it managed in the 2011 elections and close to the record high 28.9 per cent it won in 2007.

But Mr Pascal Sciarini, a political scientist at Geneva University, noted a heightened feeling of solidarity towards the migrants moving through Europe, which "may not benefit SVP".

He suggested that the party, which in 2007 sparked outcry with posters of three white sheep kicking a black sheep off the Swiss flag, had toned down some of its anti-immigrant rhetoric.

The centre-right Liberal Party, Switzerland's third largest, has also seen a significant hike in support in the latest polls to 16.7 per cent.

But it holds a very different view from the SVP, stressing instead the need for more immigration to keep Switzerland's economy strong.

"There is no migration problem... The main problem facing Switzerland today is economic," Liberal lawmaker Fathi Derder told Agence France-Presse, warning that the country, where unemployment stands at just over 3 per cent, faced "a dire lack of qualified labour".

The Socialists, Switzerland's second-largest party, which in the last polls inched up slightly from the 18.7 per cent of the vote they won in 2011, want to broaden the debate to include cleaning up the Swiss banking sector and improving ties with the EU.

A shift to the right in Parliament could have dire consequences, Socialist vice-president Roger Nordmann warned, especially if it hands more influence to SVP, whom he accused of "playing to xenophobia".

AGENCE FRANCE-PRESSE