By Gernot Heller and Michelle Martin
BERLIN (Reuters) - The youth wing of German Chancellor Angela Merkel's conservatives on Friday demanded the bloc renew itself and build up a successor, warning it does not have much time after securing a much criticised coalition deal.
Desperate to put a government in place and end more than four months of political limbo in Europe's largest economy, Merkel made heavy concessions to the Social Democrats (SPD) and upset many in her party by agreeing to hand them the powerhouse Finance Ministry.
The chancellor, who long seemed impervious to criticism from within her own ranks, has faced a barrage of complaints since Wednesday's agreement, which left her bloc with six ministers - the same number as the SPD, which fared considerably worse in September's national election.
Discontent runs so deep that her party colleagues are even starting to talk about who should ultimately replace her. That marks a major shift since Merkel has not previously faced a credible challenge to her rule in the more than 12 years she has spent at the helm of Europe's pre-eminent power broker.
Some commentators have suggested a mid-term review due two years in to the government could offer Merkel the opportunity to step gracefully aside.
Paul Ziemiak, leader of the youth wing of the Christian Democrats (CDU) and Christian Social Union (CSU) that together make up Merkel's conservative bloc, said the party needed to think about who would take over from Merkel, now on the brink of a fourth term.
If the CDU does not make headway with a renewal that puts up fresh faces and increases diversity "the mood will remain very, very bad", he told German broadcaster Deutschlandfunk.
"We want younger people, younger politicians to be part of the government and party leadership," he said. "We don't have much more time."
With around 115,000 members, the youth wing, which say it is Europe's biggest political organisation for young people, carries influence within the party.
Ziemiak said Merkel needed to make clear by the time of a CDU congress on Feb. 26 how staffing in the government and party would look in future.
"Dissatisfaction is very strong among grassroots CDU members," he said. Many members thought the CDU had failed to negotiate well, he said.
Friedrich Merz, a long-time Merkel rival, told Bild newspaper the CDU would undermine itself if it accepted the "humiliation" that came with the division of ministries.
And Norbert Roettgen, a foreign policy expert in the party, told the same newspaper the way the portfolios had been carved up meant the CDU would be structurally weakened and have less influence on government in future.
The SPD's 464,000 members still have the right to veto a "grand coalition" with Merkel's conservatives and the result of a postal ballot is due to be announced on March 4. Many grassroots SPD members oppose such an alliance, especially after their party got its worst postwar election result in September.
Kevin Kuehnert, leader of the SPD's youth wing, is travelling around the country urging members to say "no".
Foreign minister Sigmar Gabriel, who is set to lose his job to party leader Martin Schulz if the coalition is formed, is also a malcontent, bemoaning the "lack of respect" his labours had received and cancelling a row of official appointments.
(Writing by Michelle Martin)