Uncertainty surrounds the nature of the suspect device contained in an item of luggage due to be loaded on a Munich-bound Air Berlin flight at Windhoek yesterday.
Air Berlin notably states that the luggage was unlabelled, and that it could not be attributed to any specific flight or individual.
But the carrier adds that it is unable to determine whether the threat was genuine or whether the luggage had been part of a security test.
A spokeswoman for Air Berlin stresses that the luggage was "not on board" the Airbus A330, which was transporting 296 passengers and 10 crew, when the item was intercepted.
The twin-jet was being operated by Air Berlin's long-haul division LTU.
Germany's federal police authority, the Bundeskriminalamt, has stated that examination revealed a clock, batteries and a detonator, although it has not confirmed the presence of any explosive compound, or said whether the device was a viable weapon.
Nambia Airports Company could not immediately be reached for comment on the situation.
Timing of the discovery is particularly notable given that it coincided with a statement issued by German federal interior minister Thomas de Maiziere, citing evidence of an increased terrorist threat against Germany.
De Maiziere highlighted the concealment of explosive devices on board freight flights from the Middle East last month as testimony to the "adaptability and persistence" of perpetrators of terrorist activities.
German law-enforcement authorities have been instructed to tighten security at airports and rail stations.
De Maiziere says there is "cause for concern, but no reason for hysteria" but states that measures are being put in place aimed at prevention and deterrence.
Last month's interception of explosive devices in the air cargo system came days after criticism from the air transport industry that certain security measures were unnecessary.