A tense truce within German Chancellor Angela Merkel's conservative camp shattered Thursday after her hardline interior minister defended protests marred by neo-Nazi violence and blasted migration as "the mother of all political problems".

German Chancellor Angela Merkel said deals on migration she had brought home from Brussels should be enough to satisfy her restive Bavarian allies, who were gathering in Munich on Sunday afternoon for a meeting that could decide her political fate.

German Chancellor Angela Merkel has drawn up a raft of measures to tighten controls on the influx of migrants, according to a document submitted to her coalition partners Saturday as she battles for political survival.

Germany sealed deals with Greece and Spain Friday to take back migrants previously registered in those countries, in a crucial win for Chancellor Angela Merkel as she faced a weekend deadline to heal a deep rift within her fragile ruling coalition.

German Chancellor Angela Merkel said on Friday on a visit to Lebanon that conditions in Syria are not yet right for refugees to return, an issue which has led to a dispute between Lebanon's foreign minister and the UN refugee agency.

Angela Merkel's conservative alliance may splinter in a row over immigration, an ally of the German chancellor said on Friday, as the third party in her fragile government suggested its patience was wearing thin.

The German chancellor gave an extensive newspaper interview on Sunday that touched on reform of the euro zone as well as defence and asylum policy.

Lawmakers in Berlin's glass-domed Reichstag voted 364-315 with nine abstentions for Angela Merkel who was then to be formally appointed by President Frank-Walter Steinmeier.

Germany's Foreign Minister Sigmar Gabriel said on Thursday he would not join Chancellor Angela Merkel's coalition government, opening the way for a new SPD figure in the high-profile post.

Chancellor Angela Merkel on Sunday vowed to work with the Social Democrats for the "good of Germany" as the centre-left party agreed to join her new coalition.

Members of Germany's Social Democrats (SPD) voted in favour of a coalition with Chancellor Angela Merkel's conservatives on Sunday, opening the way to a new government for Europe's largest economy.

Angela Merkel said: "The killing of children, the destruction of hospitals -- all that amounts to a massacre that must be condemned and which must be countered with a clear no".