The prospect of a party that has been compared to the Nazis entering the heart of German democracy is unnerving the other parties ahead of the federal election.
The first far-right party set to enter Germany's parliament for more than a half a century says it will press for Chancellor Angela Merkel to be "severely punished" for opening the door to refugees and migrants.
The Alternative for Germany (AfD), which has also called for Germany's immigration minister to be "disposed of" in Turkey where her parents come from, could become the third largest party with up to 12 per cent of the vote on September 24, polls show.
That is far less than similar movements in other European countries - in France far-right leader Marine Le Pen won 34 per cent of the vote in May and in the Netherlands far-rightist Geert Wilders scored 13 per cent in a March election.
But the prospect of a party that the foreign minister has compared with the Nazis entering the heart of German democracy is unnerving the other parties. They all refuse to work with the AfD and no one wants to sit next to them in parliament.
Leading AfD candidate Alexander Gauland denies they are Nazis, saying others only use the term because of the party's popularity. It has won support with calls for Germany to shut its borders immediately, introduce a minimum quota for deportations and stop refugees bringing their families here.
"We're gradually becoming foreigners in our own country," Gauland told an election rally in the Polish border city of Frankfurt an der Oder.
A song with the lyrics "we'll bring happiness back to your homeland" blared out of a blue campaign bus and the 76-year-old lawyer said Germany belonged to the Germans, Islam had no place here and the migrant influx would make everyone worse off.
Gauland provoked outrage for saying at another event that Germans should no longer be reproached with the Nazi past and they should take pride in what their soldiers achieved during the World Wars.
The AfD could end up as the biggest opposition force in the national assembly if there is a re-run of the current coalition of Merkel's conservatives and Social Democrats (SPD) - one of the most likely scenarios.
That would mean it would chair the powerful budget committee and open the general debate during budget consultations, giving prominence to its alternatives to government policies.
Georg Pazderski, a member of the AfD's executive board, told Reuters his party would use parliamentary speeches to draw attention to the cost of the migrant crisis, troubles in the euro zone - which the AfD wants Germany to leave - and problems related to the European Union.
Gauland said the AfD would call for a committee to investigate the chancellor after entering parliament: "We want Ms Merkel's policy of bringing 1 million people into this country to be investigated and we want her to be severely punished for that."
Unlike previous right-wing movements in Germany the AfD - founded in 2013 by an anti-euro group of academics - has become socially acceptable so radicalised people from the middle class feel able to vote for it alongside classic radical right-wing voters, said Manfred Guellner, head of Forsa polling institute.
"You don't vote for skinheads but you can vote for professors in suits," said Guellner, referring to the likes of Gauland, who tends to wear tweed jackets.