As a result, the VVIP flight, which besides the German Chancellor had a large delegation on board, had to circle over Turkey for two hours before being given permission to enter Iranian airspace in the wee hours on Tuesday, May 31, German paper Der Spiegel reported.
The flight was finally allowed to fly over the Iranian airspace - the normal flight route between Europe and India - following a hour-long negotiation with Tehran which was mediated by Turkey and involved the Foreign Ministry in Berlin, it said.
Merkel on her way to India arrived late in New Delhi this morning as a result of the delay.
"There has never been an incident like this," said German government spokesman Steffen Seibert.
Berlin would now consider whether it would lodge a diplomatic protest, he said.
However, a second aircraft carrying several members of Merkel's cabinet, including Defence Minister Thomas de Maizi�re and Interior Minister Hans-Peter Friedrich, was able to cross Iranian airspace without any problems. It had left Berlin before Merkel's plane.
The reason for the denial of overflight rights was initially unclear. Before the plane left Berlin on Monday evening, May 30, it had been given permission to enter Iranian airspace.
The aircraft was the inaugural flight of the new government plane "Konrad Adenauer," an Airbus A340-300.
The incident could further sour relations between Berlin and Tehran, the paper said.