The case came to light on Wednesday when commercial broadcaster MTV3 published news of an NBI list it had obtained. Putin's named was added to the list last November after he gave an award to a leader of a motorcycle gang.
"The National Bureau of Investigation has made a mistake and apologises for what has happened," said NBI Deputy Chief Tero Kurenmaa.
The NBI maintains that Putin’s name should never have been on the register. The individual responsible for adding his name has begun to talk, but Kurenmaa would not shed further light on the investigation during the press conference.
"There is no reason to suspect Putin of any crime," stated Kurenmaa.
Earlier Finland's president Sauli Niinistö had said that a mistake of this nature raised broader questions about the way police collect data. Interior Minister Päivi Räsänen apologised on Wednesday, as did National Police Commissioner Mikko Paatero.
The case has been covered by media across the globe. Putin's spokesman told a Moscow radio station that the Russian president reacted ironically, and that no Russian response was required as Finland had noticed and corrected the matter.