BERLIN, Oct. 20 (Xinhua) -- Germany's main opposition Social Democrats (SPD) agreed on Sunday at a special convention to start full coalition talks with Chancellor Angela Merkel's conservatives on forming a grand coalition to rule the biggest European economy for the next four years.
SPD chairman Sigmar Gabriel won the backing of senior Social Democrats at the party meeting, saying that the party aims to form a government by Christmas.
For the coalition talks to begin on Wednesday, the SPD listed "non-negotiable" demands including the introduction of a national minimum wage of 8.50 euros (11.35 U.S. dollars) per hour and more investment in infrastructure and education.
The agreement to form a grand coalition with Merkel's Christian Democratic Union (CDU) and its Bavarian sister party the Christian Social Union (CSU) came more than one month after the Sept. 22 elections when Merkel's bloc proved to be the biggest winner with 41.5 percent of votes, while the SPD took 25.7 percent.
Without a majority of the parliament seats, CDU/CSU bloc has to find a partner to form a coalition in order to rule Europe's largest economy for the next four years. A grand coalition with the center-left SPD as in Merkel's 2005-2009 first term is supported by most Germans, recent polls showed.
Merkel's spokesman Steffen Seibert has said the chancellor and cabinet will officially resign Tuesday and act as caretaker government until a new cabinet is formed. Merkel warned on Friday that a new government may not emerge until December.