The airport was originally supposed to open in June, but it was delayed until March 2013 because of problems with its fire protection systems, as well as the uncertainty of who will be paying the project's huge cost overruns, Der Spiegel reported.
The airport is $1.5 billion over budget. Operators are seeking a short-term bridge loan to cover any upcoming costs.
However, it is not clear whether the federal government is willing to give more funding to the airport project.
"Given the chaotic situation and jurisdictions, there can be no additional financial concessions granted to the new capital city airport ... in the upcoming negotiations for the 2013 federal budget," says Jurgen Koppelin, a senior member of the parliamentary Budget Committee in Berlin.
The board was set to meet Thursday to go over a new financial plan, but that meeting was pushed back until September.