Angela Merkel vowed to work with haste and optimism as she entered talks with her centre-left rivals to revive Germany's ruling coalition.
The week of meetings between Merkel's conservative alliance and the Social Democrats (SPD) will examine whether both sides have enough common ground to begin formal coalition negotiations towards a new government by March or April.
If the talks prove successful, a new government will likely be in place by Easter, she said. "We will work very swiftly and very intensively", she told reporters. "And this new era needs new politics", he said, adding that "a new political style" was also required.
Opposition to such a tie-up is strong in the SPD - a group called "NoGroKo", meaning "no grand coalition", has formed within its ranks to campaign against working with Merkel again, saying that would cost the SPD votes and make the far-right Alternative for Germany (AfD) opposition leader.
With an eye on a regional election in Bavaria later this year, where current polls show that the CSU could lose its absolute majority, the party wants financial handouts to asylum seekers reduced.
Following several violent crimes involving refugees of uncertain age who claimed to be minors, the CSU party also wants medical tests to determine if adult migrants are posing as under-18s.
Merkel arrived for exploratory talks weakened, but still the main player.
Martin Schulz, SPD leader and former president of the European parliament, said he was "not drawing red lines" and was approaching negotiations with and open mind.
The SPD initially made a decision to go into opposition, but agreed to talks after Merkel's unprecedented attempt to form a government with The Greens and the libertarian Free Democrats (FDP) failed in November.
Any deal would still have to be put to a vote of the SPD rank-and-file, and the leadership has been at pains to stress that talking with Merkel's conservatives did not automatically mean a new grand coalition.
CDU, CSU and SPD leaders said late Sunday they would discuss the necessity for wide-reaching reform. Enticing them to team up with her is Merkel's best bet of forming a stable government and extending her 12-year tenure after her efforts to form an alliance with two smaller parties failed last year.