A logo for Google is seen in a reflection. (Reuters-Yonhap)

The top South Korean court sided with internet users here on Thursday, ruling that Google should disclose records of how its consumer data had been transmitted to a US spy agency upon the request of consumers.

The ruling by the Supreme Court of Korea, after a decadelong wait, indicates that Google's policy of prohibiting the provision of such records to consumers and mandating that lawsuits be filed in US jurisdiction are both superseded by Korean law. A customer living in Korea may file a lawsuit against a business entity based in a foreign country, the ruling shows.

Seoul's top court judges also stated that records of user data transferred to US investigative authorities should be provided if the user's US case has been closed.

The final court judgment on California-based Google in Korea will be domesticated or put into effect in the US through recognition and enforcement by a US court, according to Korea's Supreme Court.

This decision signals an end to the legal fight of human rights activists here against the US-based Big Tech giant that has persisted for nearly a decade.

Six activists filed a suit against Google and its Korean unit in 2014 upon revelations by high-profile whistleblower Edward Snowden the previous year that the US National Security Agency had spied on internet users via tools to collect user data by operating a secret program called Prism.

The plaintiffs suspected that user data such as emails could have been monitored by the NSA under the revealed scheme.

A district court in 2015 sided with Korean consumers regarding Google's duty to disclose the data collection by the US authorities, but dismissed the request for Google to pay compensation to consumers.

Seoul High Court in 2017 upheld the district court ruling, but on the condition that Google would not breach US privacy rules.

The case at the Supreme Court had four plaintiffs, after two others dropped out of the litigation.

“We will review the Supreme Court’s full written decision carefully. ... We remain committed to making ongoing updates that give users in Korea control and transparency," a Google spokesperson said in a statement.