The CDU is protesting against criticism by the FDP about the Chancellor and their demand for a complete staff renewal of the party.
The deputy CDU leader, Julia Klockner, has defended Chancellor Merkel saying that she can not be blamed for everything.
The German Chancellor failed to clinch a majority win in the elections in September and so she failed to form a coalition government, which has left Germany without a government for 13 weeks.
Ms Klockner said: “I think we should all refrain from blaming each other for failing”.
The FDP General Secretary, Nicola Beer, called for a reform of the CDU on German radio.
She said: “She has been working to achieve the continuation of the grand coalition.
“Either the Chancellor is at the forefront of this movement or she will have to be replaced by new generations.”
The German Chancellor has been embroiled in coalition talks since the September elections as she desperately tries to strike a deal with Mr Schulz, the former European Parliament president, in order to form a government.
The vice chairman of the FDP, Wolfgang Kubicki, said: “Germany will not be able to survive in the future with Angela Merkel’s recipes for the last twelve years.”
Mr Kubicki accused Merkel of having purposefully sabotaged negotiations with the FDP and Greens as part of a plan to ensure the continuation of the acting “grand coalition” between the CDU, CSU and SPD.
Mrs Merkel’s ability to form a new government has been dealt another blow as a poll by YouGov revealed that only a third of people believed she was able to from an administration before Easter.
The SPD has agreed to talks with Mrs Merkel’s CDU on January 7 and the two parties have given themselves up to mid January to broker a deal.