Some 12 million people are eligible to vote in the states of Baden-Wuerttemberg, Rhineland-Palatinate and eastern Saxony-Anhalt on Sunday.
With public misgivings growing over the 1.1 million asylum seekers who arrived in Germany last year, political analysts are forecasting large gains for the anti-immigration party, Alternative für Deutschland (AFD), in Sunday's regional elections.
German Chancellor Angela Merkel's Christian Democratic Union (CDU) party is expected to take a thrashing in this weekend's "Super Sunday" vote.
Over the weekend the anti-immigration, far-right AFD made gains in local elections in the central state of Hessen, securing its position as the third strongest political force in the region.
Its rising popularity is being seen as a historic achievement for a party that was only founded three years ago and looked close to collapse when its founder left last July.
"What we see is that the public's unhappiness with Angela Merkel's open-door policy towards aslymn seekers has manifested itself in a deterioration in the support of the CDU," says Geman politics specialist Charles Lees at the UK's Bath University.
Opinion polls show 47 percent of the population are happy with Merkel's policy on immigration and 50 per cent are unhappy.
"There's more of an unhappiness in the east of Germany and slightly less in the west," Lees points out. "If you looked at the polls six months ago before the asylum-seeker crisis broke, Merkel was very comfortable and the CDU was ahead.
"The AFD looks like it has the potential to eat into the CDU's monopoly on the right. It's running quite well in the state elections, in the polls they appear to be very strong and, if they maintain this level of support through to the next Bundestag election, then they could cause serious problems for the CDU, eating into their vote from the right."
Immigration will be important in Sunday's elections, according to William Paterson, an honorary professor of German and European Politics at Aston University in the UK.
"It is a key issue because there are very few other issues; Germany has done very well," he told RFI. "Suddenly, almost out of the blue sky, last summer, immigration becomes a key issue.
"There is some opening to the far right, mainly concentrated in what was Eastern Germany, but it's still a minority. Any solution to the refugee crisis depends on cooperation from other EU members and a willingness of other EU members to bear part of the burden and that's just not there.
Paterson believes the threat from the AFD is exaggerated in the immediate future.
"Clearly, the longer it is not possible to find a solution to the refugee question, then the worse it is for the Chancellor," he adds. "She is protected by two things. First of all, the [centre-left] SDP party is so weak. And secondly, there is no conceivable rival in the immediate future."