"I can confirm that Apple was not authorised to take aerial photographs because the level of detail in the shots is considered too high for some of the restricted zones," a spokeswoman for the Norwegian National Security Authority (NSM), Mona Stroem Arnoey, said.
"We have however presented Apple with alternative solutions, including buying photos from Norwegian suppliers or from the Norwegian map authorities," she said.
Norway's neighbours Sweden and Denmark have meanwhile granted Apple permission to take aerial photos.
NSM, tasked with protecting Norway from espionage, sabotage or acts of terrorism, refused to comment on the number or nature of restricted zones in Oslo.
Photos of these zones provided by Norwegian suppliers are of a lower resolution or blurred.
According to the daily newspaper Aftenposten, the photo ban prompted Oslo's mayor approached by the US embassy in Norway to contact the government on Apple's behalf but to no avail.
Apple was heavily criticised for errors in the first map application it developed in-house, and has since come up with its Flyover function that enables users to fly over major cities interactively.
Contacted by AFP, Apple was not immediately available for a comment.
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