German Chancellor Angela Merkel's plane, headed for the G20 summit in Argentina, made an emergency landing in Cologne on Thursday due to a technical problem, the Chancellery said.

"Following a technical problem, the official plane landed safely in Cologne," it said, without indicating when she could leave again.

The Airbus A340-300, named Konrad Adenauer after Germany's first post war chancellor, was met on the tarmac by fire engines, the German news agency DPA said, adding that Merkel was waiting for a replacement plane to taker her to Buenos Aires.

The plane turned back from the Netherlands and landed in Cologne because it was the only base with a a replacement plane, the news agency said.