The United Nations' expert on racism called for the poster to be withdrawn.
The SVP's focus on crime and immigration has captured the headlines in recent weeks and its aggressive campaigning has broken with the consensual traditions of Swiss politics.
Anger spilled over into a riot during an SVP rally in Bern on October 6 when police clashed with demonstrators.
The virulent campaigning prompted Doris Leuthard, the Swiss economy minister, a Christian Democrat, to warn that it could frighten away foreign investors.
The Free Democrats (FDP) took 15.9 per cent of the vote in the alpine nation, a slight decline from 2003, while the centre-left, family-friendly Christian Democrats were steady at 14.6 per cent.
The Greens took 9.5 per cent of the vote, an increase of 1.8 percentage points.
Voters cast their ballots to fill 200 seats in the National Council, the lower house, on a proportional basis.
They also voted to elect 46 cantonal representatives to the Council of States, the upper house.