South Korea and the United States should not shy away from bilateral talks with North Korea to address its ever-growing nuclear and missile threats, a former senior US diplomat said Wednesday, adding that diplomacy will be the only way to find a solution to such a tricky problem.

"There will come a time when we are going to have to double down on diplomacy because it's probably through diplomacy that we have the only way to find a solution to this difficult problem," former Deputy Secretary of State John Negroponte said in his keynote speech at a forum held in southern Seoul.

"I think we need to approach a dialogue as a means to solve problems rather than as a reward for good behavior.... Neither the US nor South Korea should shy away from bilateral talks with North Korea," he added.

Negroponte, who also served as director of national intelligence and ambassador to the UN, suggested the long-suspended six-party denuclearization talks might be one of the most effective options in tackling the prolonged nuclear stalemate.

"We need to have all the key regional players represented in any solution -- North Korea, South Korea, Japan, Russia, China and the US -- essentially the countries that were members of the six-party talks that took place in recent years," he said.

"I think the six-party format or something like that has much to command it in terms of assuring that all the most important regional interests are involved."

The six-party talks started in 2003 to persuade the North to give up its nuclear aspirations but it has not been held since late 2008 when the North walked away from the negotiating table.

North Korea conducted nuclear tests twice last year alone. On July 4, it claimed to have held a successful test of an intercontinental ballistic missile, ratcheting up tensions surrounding the Korean Peninsula and drawing strong condemnation from the international community.

South Korea recently offered to hold inter-Korean military talks on Friday to ease tensions along the tense border and Red Cross talks on Aug. 1 to resume reunions of families separated by the 1950-53 Korean War. There has been no response from the North to the overtures.

Negroponte, in particular, put great emphasis on maintaining a strong alliance between the US and South Korea to make the efforts to "peacefully" resolve the North Korea issue a success.

"As we set out to peacefully resolve this problem, I would admit to you that the greatest asset is not just our formidable armies and military capabilities but also our faith and friendship and confidence that we have in one another," he said.

"And I think that one of the most pivotal elements, if not the most pivotal element, of any strategy of dealing with North Korea is harmony between Seoul and Washington. To this end, the Moon and Trump governments have gotten off to a very good start in us working closely together," he added, referring to the summit held later last month in Washington. (Yonhap)