The official Korean Central News Agency said last weekend the North Korean government was interested in "high-level talks" with the U.S. government to establish security on the Korean Peninsula.
Multilateral nuclear talks among the two Korean governments, the United States, China, Japan and Russia ended in 2008. North Korea has conducted three nuclear tests since then.
South Korean Unification Ministry spokesman Kim Hyung-suk said direct talks are unlikely without a direct South Korean role.
"There is little to worry of Pyongyang trying to bypass the South to talk directly with the United States," he was quoted by South Korean news Yonhap as saying.
He said the South Korean government was frustrated because of a decision to cancel talks at the border town of Kaesong. Operations at an inter-Korean industrial complex at the border town were shuttered in April as a consequence of ongoing regional tensions.
Kim said "a sincere attitude" from North Korea was needed before the South Korean government took diplomatic gestures seriously.