Health Minister Jens Spahn said the CDU had watered down its profile by becoming too centrist in the past years.
Merkel said Monday she would not stand for re-election in December as leader of her centre-right CDU party, but that she planned to see out her fourth term as German leader.
Merkel told party top brass her mandate running to 2021 will be her last term, adding she has no plans to seek a post in the European Commission following that despite speculation to that effect in Brussels.
All three parties in German Chancellor Angela Merkel's coalition have recently been losing ground to the far-right Alternative for Germany.
Annegret Kramp-Karrenbauer is set to become the secretary-general of the CDU, taking over from Peter Tauber.
After German Chancellor Angela Merkel's CDU made many concessions to the SPD, the Young Union has demanded that the CDU find a successor to Merkel.
The CDU and SPD's proposed coalition may be splintered by disagreements over healthcare and labour issues.
A coalition between the SPD and CDU has been jeopardized by disagreements over a myriad of issues.
German Chancellor Angela Merkel's party, the Christian Democratic Union, has agreed to attempt to broker a coalition with the Social Democratic Party.