North Korea has said it is scrapping all accords with South Korea, claiming they are on the brink of war.

The latest rise in tension has increased the chances of a military clash on the strongly defended border that has divided the two Koreas for more than half a century, analysts said.

"There is neither way to improve (relations) nor hope to bring them on track," the North's Committee for the Peaceful Reunification of Korea said.

"The confrontation between the North and the South in the political and military fields has been put to such extremes that the inter-Korean relations have reached the brink of a war."

KCNA also criticised South Korean President Lee Myung-bak over the appointment of a new minister in charge of relations on the peninsula, saying he was an architect of the government's "undisguised policy for confrontation with the DPRK (North Korea)".

The North in recent months has repeatedly warned of war on the divided peninsula and threatened to destroy the conservative government in Seoul which has ended a decade of free-flowing aid to Pyongyang after taking office a year ago.

South Korea's presidential Blue House stuck to its policy of largely ignoring the rhetoric flying across one of the world's most heavily armed borders where over a million troops face off.

"Our position is there is no need to react sensitively or get happy or sad over every single statement issued with some political motive (by the North)," a presidential official said.

Speaking in the Swiss resort of Davos, South Korean Prime Minister Han Seung-soo said he hoped the North would hold dialogue rather than make threats.

"We hope that instead of threats of this kind, North Korea would come out to talk to us on matters of mutual concern and interest," he said.

Asked whether the timing was tied to US President Barack Obama's inauguration, he said: "I don't know what is behind their thinking, but I am sure that the inauguration of the Obama administration must have had some impact on the thinking of North Korea on global issues, as well as the issue of the Korean peninsula."

International talks to end the North's nuclear programme have been deadlocked and Pyongyang has in the past gone beyond rhetoric to make a point.

It exploded its first nuclear device in 2006 when it appeared to be increasingly left out in the cold by Washington.

The latest move follows comments by a US national security official that the secretive state's leader, Kim Jong-il, appeared to have rebounded politically from his recent health scare and is making major decisions.

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