South Korea's top court on Thursday ordered the country's three mobile carriers to reveal the breakdowns of their operating costs, which can provide the public with a clearer understanding of fees being charged.

The Supreme Court of Korea upheld the ruling made by a local high court, claiming that access to such information is a right granted by the Constitution. The announcement came seven years after a local activist group filed a lawsuit in 2011 demanding mobile carriers to make public related documents.

Following the ruling, the mobile carriers are requested to reveal the breakdowns of their earnings and related documents for the 2005-2011 period. Pundits, however, said it is more significant that the court acknowledged that the costs of mobile services can be considered as public information.

People's Solidarity for Participatory Democracy, a local advocate group, asked the country's telecom watchdog to make public the operating costs of local mobile carriers in 2011, but the government rejected the request then, claiming that such information may contain business secrets.

The group claimed telecom services have become a necessity for the vast majority of people and that certain information that affects everyday lives needs to be shared.

The country's three mobile carriers -- SK Telecom Co., KT Corp. and LG Uplus Corp. -- refrained from making official statements on the ruling.

Industry insiders, however, claimed that it is rare in other countries for a court to order mobile carriers to open such business-related information.

"The cost-profit ratio is used as an index to determine whether public companies set appropriate prices for electronics, water and gas," an official from one of the mobile carriers, who wished to remain anonymous, said, claiming that such standards should not be applied to private firms.

The official claimed that service prices also take various factors, including market competition, into consideration and that the breakdown of costs is not the only criteria.

Another official said the telecom industry should be approached differently compared to electricity and rail services that are controlled by public corporations.(Yonhap)