The row peaked this week when intelligence authorities said they would investigate a series of incidents that had occured ahead of crucial elections and which greatly swayed polls results in favor of the then ruling camp.

A list of incidents unveiled by the National Intelligence Service (NIS), which was recently cleared of supporters of former military backed-governments, included a 1987 bombing of a South Korean passenger jet.

A North Korean female agent, who was arrested in Bahrain several days after the bombing and who now lives in Seoul, confessed to planting a time bomb on the plane on orders from Pyongyang to thwart the 1988 Seoul Olympics.

The Stalinist North denied any involvement, blaming the then South Korean goverment led by former general Chun Doo-Hwan.

At the time it accused theSouth of seeking to cause a security alert to sway conservative votes away from the Opposition and to smear the North seeking to improve ties with the West.

The NIS list also contained a spate of armed shows of force by North Korean troops in the sensitive border truce village of Panmunjom in 1996 in the run-up to key National Assembly elections.

``There have been suspicions over why such provocations occurred always ahead of elections for the benefit of ruling camps,'' the NIS said Wednesday, pledging an investigation.

The NIS announcement enraged the former ruling Grand National Party (GNP), which already faces allegations by prosecutors that it sought to buy North Korea into staging a border shoot-out before the December presidential election.

"The NIS is jeopardizing national security with senseless claims," the GNP said,accusing the ruling camp of suggesting that even the plane bombing might be an int er-Korean plot.

"The NIS claims have opened up the way for the North to interfere with ourpolitics," it said.

But the NIS later said it was not suggesting the bombing was a joint conspirarybut a rebuttal against North Korea's allegations that the North was an innocent vi ctim to the South's political wrangling.

The North has threatened to "clarify the truth, when necessary," over allegations including the border shootout request.

The GNP has charged that the claims of a shootout plot were dragged out of informants by intelligence officials using torture.

But prosecutors say North Korea just failed to respond to the GNP's request allegedly designed to scare conservative voters from electing Kim Dae-Jung, a long-time dissident who narrowly beat GNP candidate Lee Hoi-Chang last December.

Lee, a former Supreme court judge, has denied knowledge of such a plot. But prosecutors argue his campaigners contacted North Koreans in Beijing with offers of aid in return for a limited show of force on the border.

The rival groups have tried to eschew a political showdown, despite bitter wranglingsparked by a prosecution probe into previous allegations that Lee illegally co llected election funds. The ruling camp wants Lee to make an open apology for illegal campaigning whichcould end his political life.

Kim Dae-Jung, 74, has said the prosecution is not political revenge, and appealeD For Opposition help to heal the ailing economy. But the GNP, which lost its majority in parliament last month, has refused to cooperate, contending the ruling camp's offensive is aimed at paving the way for tele vised hearings into the previous government's policy failures.