South Korean police have raided the Seoul office of Google as a part of the investigation over allegations that the company used its mobile phone advertising platform AdMob to illegally collect private data without taking prior permission form users.

After the raid, investigators have taken hard drives and other computer data related to its "AdMob" platform, a South Korean police cyber crime unit spokesman told AFP.

"The raid followed allegations that Google’s mobile advertising agency, AdMob, had illegally collected private data," he said.

"We suspect AdMob collected personal location information without consent or approval from the Korean Communication Commission," a South Korean police official said.

Google has confirmed the raid, saying that the police had visited its Seoul office.

A Google spokesman told Reuters that the company was cooperating with the investigation being carried out by the authorities.

Google bought the global mobile ad firm AdMob last year for $750m.