South Korean police say they have asked prosecutors to charge Google with collecting personal data while producing its Street View mapping service, and have handed over supporting evidence.
Street View allows users to see panoramic street scenes on the Google Maps site.
Google has admitted its Street View cars, which have been cruising and taking photographs of cities in more than 30 countries, inadvertently gathered fragments of personal data from unsecured Wi-Fi systems.
In South Korea, police suspect Google violated three telecommunication laws.
They say it is the first time Google could face charges for such offences in the course of investigations underway in various countries.
In Australia, the Australian Federal Police dropped its case against Google, saying that the data collection may have been inadvertent.
Police said the Google cars gathered contents of email exchanges, online messenger chats, log-in IDs, website passwords and credit card and mobile phone information belonging to about 600,000 people.
Jang Suk-Hwa, the officer heading the investigation at the national police cybercrime unit, said the case was unprecedented in terms of the number of people involved.
State prosecutors under the South Korean system make the decision on whether to press charges.
Police said last week they had decoded data on hard disks, which were confiscated from Google's Seoul office last August, and had found evidence of illegal gathering of private data.
Google repeated "profound" apologies for the accidental collection of data from unencrypted networks.
"As soon as we realised what had happened, we stopped collecting all Wi-Fi data from our Street View cars and immediately informed the authorities," the company said in an emailed statement.
"While we have repeatedly acknowledged that this was a mistake, we believe Google did nothing illegal in Korea."