Fire investigators arrive at the SK CC building located in Pangyo to inspect the cause of the fire, Oct 16. Joint Press Corp

KaKao, the operator of Korea's dominant messaging app Kakao Talk, has restored 40 percent of its data center's servers, an executive said Sunday, as it is working to fully repair its services disrupted by a fire.

The tech giant has restored 12,000 servers out of 32,000 at its data center in the SK CC building located in Pangyo, just south of Seoul, said Yang Hyun-seo, Kakao's vice president handling the company's relationship with the government.

"It is hard to tell exactly how long it will take before Kakao Talk and other services can be fully restored," she said at the site, citing a massive server loss.

Kakao has servers in Pangyo and Anyang, both in Gyeonggi Province that surrounds Seoul, as part of its risk management policy, but the fire, which has been extinguished, was unexpected, according to Kakao.