Berlin Mayor Klaus Wowereit addresses the media in Berlin, following a meeting about the future Berlin Brandenburg international airport Willy Brandt (BER), Jan 7, 2013. Wowereit said on Monday he was stepping down as supervisory board chairman of Berlin's new international airport following another postponement of the opening date for the city's flagship project.[Photo/Agencies]

BERLIN - Berlin-Brandenburg Airport, the new air harbor for the German capital, postponed its opening date again, confirmed the airport operator on Monday.

Flughafen Berlin Brandenburg GmbH, the airport operator, said in a statement that the new delay was caused by "problems with the fire protection system, in particular the fresh air supply in the case of a fire and the complexity of the system as a whole."

It has been more than two years since the airport's originally-planed opening date.

The airport, also known as Willy Brandt Airport, started its construction in September 2006 and was firstly scheduled to open in October 2011. The date, however, was postponed to June 2012 for construction reasons later.

Days before the second planned date, public was told that the new airport would not be ready until early 2013 because of security problems. Then, the new date was readjusted to October 27, 2013.

This time, "it is too early to discuss on a new opening date," said Horst Amann, the airport operator's Chief Operating Officer.

The new airport was jointly owned by the German federal government and states of Berlin and Brandenburg, who hold the stakes of 26 percent, 37 percent and 37 percent respectively.

According to Flughafen Berlin Brandenburg GmbH, representatives of joint owners met the management team from the operator on Monday to discuss progress on the construction of the new airport.

The airport operator's supervisory board would discuss further action and the consequences of the new postpone at its next meeting later this month.

The repeated delays of the new airport has made some Germans feel embarrased. "What a disgrace!" wrote the massive circulation German newspaper Bild on Monday, accusing that "the capital disgraced the whole country."

The paper said the new airport would not open until "at the earliest possible of 2014", citing an "internal document" that it claimed to get.

Until the opening of the new airport, Berlin would have to rely on the two small air harbors of Tegel and Schoenefeld. In 2012, the two aging airports handled more than 25 million passengers.

Delays had also dragged airlines into trouble. In November 2012, Airberlin, Germany's second largest airline, filed a suit against the new airport's operator, claiming damages resulting from the delays.

Airberlin planned to use Berlin-Brandenburg Airport as its new international hub and had undertaken its flight plans for Berlin "on the basis of the infrastructure of the new airport and the opening date assured by the airport operator," said the airline.

More than 230 additional flights per week has been scheduled to Berlin in summer 2012, when the airport was originally planned to open. All these flights, have to fly to Tegel airport, which the airline said was already operating "at the limits of its capacity and even with the most committed engagement of the airport staff," leading to "tens of millions (euros)" of additional costs and losses.