Lawmakers denounced Japan's actions against South Korea's top internet portal operator as "excessive," saying they potentially throw cold water on the improving bilateral relations, and urged Japan on Friday to quickly and wisely resolve a simmering row over Japan's demand for South Korea's internet platform operator to reduce its presence in Japan's most popular mobile messenger app.

Tokyo demanded LY Corp., the operator of Line, the most widely used messenger in Japan, take actions, including its financial dependence on South Korean tech company Naver Corp., which holds a stake in LY's holding company, citing a recent data leak of personal information.

The measures include Naver divesting its stake in A Holdings, which controls LY.

A Holdings -- a 50:50 joint venture between Naver and SoftBank -- holds a 65 percent stake in LY.

Rep. Yoon Sang-hyun of the ruling People Power Party made the call during a forum, casting the measures taken by the Japanese government as "excessive" to a degree that it could be applied to a hostile country.

"It's natural for the Japanese government to take steps to prevent a recurrence, but demanding the sale of its stake, instead of a fine or penalty, seems a little excessive," Yoon said in a forum hosted by the Sejong Institute.

"Naver never illegally used the user information," Yoon said. "It appears to be an excessive measure that could be imposed on a hostile country."

Japan's Kyodo news agency reported that Japan's Ministry of Internal Affairs and Communications issued the administrative guidance to LY over the leakage of over 300,000 cases of data leak last year, including handing over its stake to SoftBank Group, which also has a stake in A Holdings.

Japan's move prompted criticism in South Korea that it is aimed at reducing foreign influence in the online platform most widely used in the country.

Yoon said the fact that Japan has asked South Korean authorities to cooperate in its investigation into Naver's cloud system over the data leak is "beyond intolerable."

"Japan's moves can throw cold water on the bilateral relations that have created the momentum for a great turnaround," he said.

"I call on the Japanese government to show a willingness to deal with this issue and resolve it wisely, at an early date, so that it won't be an obstacle to the bilateral relationship," Yoon said.

Lee Yong-sun, a lawmaker from the main opposition Democratic Party, said the recent row involving Naver is not understandable if the two countries are in cooperation for common systems and values.

"New issues are arising as the Korea-Japan relations are feeble to ignition, and it does not make sense to change a governance system to solve security problems," Lee said.

In an earnings call earlier in the day, Naver CEO Choi Soo-yeon said the company has not decided on a position on the issue but will address the matter from a long-term business point of view.

She said that it's not about following Japan's demand or not, but more about shaping the business strategy. (Yonhap)