"The United Nations has asked the German government to stay on in its commanding role for another rotation period," foreign ministry spokesman Jens Plötner told a press conference.
"We understand from New York that the request is based on a desire for continuity regarding the mission in Lebanon."
UNIFIL was deployed in the aftermath of Israel's devastating 34-day war last summer on Hezbollah guerrillas in Lebanon.
Its naval component is meant to prevent arms being smuggled to Hezbollah by sea and has been headed since October by a contingent of some 850 German sailors.
Open to request
Chief government spokesman Ulrich Wilhelm said Berlin received the UN request for an extension in April after Chancellor Angela Merkel indicated during a visit to Beirut that Germany would consider such a demand.