North Korea is ready to conduct another nuclear test if its current approaches for dialogue fail although there are no current signs of preparations, South Korea’s spy chief said Tuesday.

“Another atomic test is always possible as (North Korea) has various nuclear test sites and construction of (new) sites is under way,” National Intelligence Service chief Won Sei-Hoon was quoted as telling a parliamentary intelligence committee.

Won’s comments to the closed-door session were quoted by ruling party lawmaker Hwang Jin-Ha.

North Korea conducted its first two nuclear tests in October 2006 and May 2009.

The South’s Yonhap news agency reported in February that the North was digging at least two new tunnels at its nuclear test site in apparent preparation for a third atomic detonation.

“I believe North Korea will use military action such as nuclear and missile (tests) to turn the tables if its current tack of dialogue fails,” Won said.

Multinational talks on ending the North’s nuclear programmes in return for diplomatic and economic benefits have been stalled since December 2008.

Pyongyang has expressed interest in restarting them. But Seoul and Washington say it should first show it is serious about disarmament and mend cross-border ties.

The North fuelled regional security fears last November by disclosing an apparently functional uranium enrichment plant, which could give it a second way to make atomic bombs in addition to its plutonium stockpile.

Lawmaker Hwang said Won expressed concern over the safety of the North’s ageing nuclear facilities at Yongbyon.

“They appear to be inferior, but we cannot say exactly which part is weak. So we’re paying attention to this problem,” the spy chief was quoted as saying.

Regarding the uranium enrichment plant, South Korean officials have questioned whether Pyongyang can build a facility that meets international safety standards.

Yongbyon for decades has been at the heart of the North’s drive for nuclear weapons, with a gas graphite reactor there having produced enough plutonium for possibly six to eight bombs.