Chancellor Angela Merkel has expressed optimism over the talks.
"I think that it can be done. We will work very swiftly and very intensively. At the same time it is clear to me that we will have an enormous piece of work in front of us over the next few days but we are willing to take it on and to bring a good result," she said."
According to the CDU/CSU statement published on Wednesday, the talks will last through January 11. The parties will prepare a final statement based on the results of the talks.
Also on Wednesday, SPD leader Martin Schulz said that the sides had set up a good foundation for the upcoming preliminary talks.
The CDU/CSU alliance has already attempted to form a government with the Greens and the Free Democratic Party, but the coalition talks failed. The latest parliamentary election in Germany was held in September 2017.