German Chancellor Angela Merkel has pushed back against critics within her Christian Democratic Union party of the government coalition deal the party reached with Germany's main center-left party.

Merkel's conservative bloc reached a deal to form a new coalition government with the Social Democrats on Wednesday, ending months of political gridlock.

The chancellor acknowledged in a Sunday interview with ZDF public television that it "was painful" to hand the powerful finance ministry to the Social Democrats.

Merkel said: "We sure did pay a price for a stable government."

But she said it would have been "irresponsible" to allow the negotiations to collapse.

Several prominent members of Merkel's party have criticized her in recent days for handing the finance, foreign and labor ministries to the Social Democrats.