Key Bavarian allies of Angela Merkel's party conceded Tuesday that the centre-left's Olaf Scholz has the best chance of becoming Germany's next chancellor, putting the conservatives on the brink of sitting on the opposition benches after the vote debacle.

Armin Laschet's CDU-CSU conservative alliance brought home its worst election result in post-war Germany of 24.1 percent in Sunday's election, behind Scholz's Social Democrats (SPD) on 25.7 percent.

Olaf Scholz's Social Democrats narrowly beat the conservatives
Olaf Scholz's Social Democrats narrowly beat the conservatives AFP / Odd ANDERSEN

But Laschet, head of the CDU and the conservative bloc's hope to succeed Angela Merkel, has insisted his party will still try to build a governing coalition and is ready for talks with the Greens and the liberal FDP for a possible partnership.

After huddling for the first meeting of its newly elected MPs on Tuesday, the Bavarian CSU pulled the rug under Laschet by declaring the SPD should be first in the queue to form the next government.

"The SPD is not too far ahead, but it is ahead of the (conservative bloc)," said Alexander Dobrindt, the parliamentary leader of the CSU, adding the bloc should therefore expect that other parties "are talking to the SPD first".

Germany's conservative Christian Democratic Union leader Armin Laschet is the frontrunner by a whisker to succeed Angela Merkel as  Chancellor
Germany's conservative Christian Democratic Union leader Armin Laschet is the frontrunner by a whisker to succeed Angela Merkel as Chancellor AFP / Tobias SCHWARZ

"Olaf Scholz clearly has the better chance of becoming chancellor at the moment," Bavarian premier Markus Soeder added, insisting the election result "must be accepted, it is a basic rule of democracy".

The CSU's stance sets the stage for a stormy session later Tuesday when its newly elected MPs sit down together with those of the CDU for the first time since the vote.

Candidate for Chancellor Armin Laschet (C) leaves the the Bundestag after his CDU-CSU conservative alliance brought home its worst election result in post-war Germany
Candidate for Chancellor Armin Laschet (C) leaves the the Bundestag after his CDU-CSU conservative alliance brought home its worst election result in post-war Germany AFP / John MACDOUGALL

Though he had admitted he could "not be satisfied" with the election result, Laschet had also claimed "no party" -- not even the Social Democrats -- could claim a mandate to govern from Sunday's vote outcome.

Possible coalitions after the German elections
Possible coalitions after the German elections AFP / Cléa PÉCULIER

But calls were growing louder Tuesday for Laschet to admit defeat and resign, even from within his own party.

"You have lost. Please have some insight. Avert further damage to the #CDU and resign," Ellen Demuth, a CDU member of the Rhineland-Palatinate state parliament, wrote on Twitter.

"We lost the election. Full stop," said Tilman Kuban, the head of the CDU's youth wing.

The conservatives lost the constituency Angela Merkel (L) had held since 1990
The conservatives lost the constituency Angela Merkel (L) had held since 1990 AFP / John MACDOUGALL

Elected as head of the CDU in January, Laschet was for some time the clear favourite to succeed Angela Merkel when she bows out of politics after Sunday's election.

But his party's ratings began to slide as he committed a series of gaffes, including being caught on camera laughing in the background during a solemn tribute to flood victims.

Sunday's result is the first time the CDU and CSU, a dominant force in German politics since World War II, have scored under 30 percent in a general election.

The vote also saw a number of CDU heavyweights lose their direct mandates, including Economy Minister Peter Altmaier, Defence Minister Annegret Kramp-Karrenbauer and Agriculture Minister Julia Kloeckner.

Merkel's former constituency on Germany's Baltic Sea coast, which she had held since 1990, went to an unknown from the SPD.

Official figures showed former CDU voters abandoning the party in droves, mostly in favour of the SPD and the Greens. But the party also lost ground to the far-right AfD in the former East Germany.

Economy Minister Peter Altmaier called the performance a "crushing defeat" for the CDU, admitting the party had "lost many swing voters".

Michael Kretschmer, the state premier of Saxony, told the MDR broadcaster on Monday he saw no clear mandate for the CDU to try to form a government.

"I see a strong message from voters, who have made it clear that the (CDU-CSU) is not the first choice this time," he said.

In a survey for the Funke media group on Monday, 70 percent of respondents said they thought Laschet should resign. Even among CDU supporters, the figure was 51 percent.

And in another post-election poll for Der Spiegel magazine, 63 percent said they thought Scholz should be Germany's next chancellor, with only 24 percent backing Laschet.