German Chancellor Angela Merkel called on the German parliament to grant a mandate to her government to start negotiations on a third bailout program for Greece on Friday, warning that chaos would be caused without a deal.

Speaking on a special session of Bundestag, the lower house of German parliament, Merkel said a third bailout was the only possible option to save Greece and European solidarity.

Other alternatives, debt haircut and Greece's exit from the euro zone, were not possible solutions, but rather the end of Europe's "legal community" and "solidarity".

"The alternative to this agreement would not be a 'time-out' from the euro ... but rather predictable chaos," she told lawmakers.

The chancellor said many people doubted the third bailout could save Greece, but "we would act irresponsibly if we didn't at least try this way".

She added that the decision was not only about Greece, but also about a strong Europe.

German lawmakers are scheduled to decide on granting the negotiations mandate later on Friday. In test votes held Thursday, a majority of Merkel's conservative CDU/CSU union and its junior coalition partner SPD were in favor of giving a green light to start the formal talks on the third rescue of Greece.