Germany's biggest political parties reached a deal Friday to form a coalition government, a senior Social Democratic official said, sealing an accord that would make Angela Merkel the nation's first female chancellor.

Merkel's primary task will be reviving Germany's economy while taming its huge budget deficit.

"It is an ideal coalition treaty," Social Democratic lawmaker Wolfgang Thierse said.

The deal still needs to be endorsed by Merkel's Christian Democratic Union, its Bavaria-only Christian Social Union sister party and the center-left Social Democrats of outgoing Chancellor Gerhard Schroeder. The parties will convene Monday to vote.

Approval by the parties would allow parliament to elect Merkel chancellor on Nov. 22.

The two sides were forced into talks on a so-called "grand coalition" — only the second in post-World War II Germany — after the country's Sept. 18 election gave neither a majority to govern with their preferred smaller partners.