Polls opened early Sunday in three state elections in Germany, which give more than 13 million voters the chance to cast their verdict on Chancellor Angela Merkel's management of the refugee crisis.
The last polling data released ahead of the elections in Baden-Wuerttemberg, Rheinland-Palatinate and Saxony-Anhalt show Merkel's Christian Democrats (CDU) receiving a drubbing that could leave it weakened ahead of a national election in 2017.
The chancellor's insistence on keeping German borders open - despite the arrival of over 1 million asylum seekers in 2015 - has lost her party many traditional supporters on the right.
The Politbarometer poll released late Thursday showed the CDU losing its status as the biggest party in the key state of Baden-Wuerttemberg, falling to 29-per-cent support.
The data show the environmentalist Greens taking the top spot in the prosperous south-western German state at 32 per cent - the first time the Greens would finish first in any state parliament.
In Rhineland-Palatinate, the CDU was set to fall marginally behind its centre-left coalition partner, the Social Democratic Party (SPD) - with the two polling 35 per cent and 36 per cent respectively.
A weakened CDU has allowed the right-wing Alternative for Germany (AfD) to make unprecedented gains and polls show it clearing the hurdle to enter all three state parliaments - another first for German politics.
At 32 per cent of the vote, according to the Politbarometer poll, Merkel's party is likely to remain the strongest entity in Saxony-Anhalt, but the data shows the AfD surging to a record 18 per cent in the eastern state.