South Korean police today raided Google's local office to investigate whether the global search company used its mobile phone advertising platform to illegally collect private data.

Investigators were sent to Google's Seoul office to secure hard drives and other computer data related to its "AdMob" platform, a police cyber crime unit spokesman said.

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

Google officials were unavailable for comment.

In January police probed Google for collecting personal data while producing its Street View mapping service, which allows users to see panoramic street scenes on the Google Maps site.

Google admitted its Street View cars, which have been cruising and taking photographs of cities in over 30 countries, inadvertently gathered fragments of personal data from unsecured WiFi systems.

But it said it did nothing illegal in South Korea and state prosecutors have yet to press charges.

The latest raid came a week after South Korea's telecoms regulator launched an inquiry into Apple to see whether the US giant's collection of location data from its iPhone and iPad users violates privacy rules.