Angela Merkel’s ruling Christian Democrats (CDU) have suffered poor results in two key regional votes seen as an indication of what might happen in September’s general election.
The CDU won about a quarter of the vote in Baden-Württemberg and Rhineland-Palatinate.
The two western states were once conservative strongholds.
Mrs Merkel is due to step down as German chancellor in September, after 16 years in office.
The slump in the CDU vote comes amid anger in Germany at the slow pace of the coronavirus vaccine rollout and a mask procurement scandal.
Several conservative lawmakers have quit over allegations they received huge commissions for arranging government deals to buy face masks.
In Baden-Württemberg the Green Party is predicted to hang on to power with about 33% of the vote, with the CDU getting 24%, less than at the previous poll in 2016.
In neighboring Rhineland-Palatinate, the centre-left Social Democrats (SPD) are projected to retain power with about 36%.
The CDU had led in opinion polls but is predicted to get only 28% of the vote.
CDU Secretary-general Paul Ziemiak said it was “not a good election evening for the CDU”.
