The call comes as tension has started to rise again on the divided peninsula, which had looked close to war late last year, with the DPRK expressing outrage at this week's military exercises by the RoK and its US ally and for dropping leaflets across the border with details of the unrest sweeping through the Middle East.

"We are prepared for dialogue with the DPRK at any time and with an open mind," Lee Myung-bak said during a speech marking the anniversary of a 1919 anti-Japanese uprising.

He reiterated a previous pledge that the RoK was willing to help its impoverished neighbor.

Tension between the two rose to its highest since the 1950-53 Korean War, after the RoK accused the DPRK of sinking one of its naval ships and later bombarding a South Korea island.

Pyongyang denies any involvement in the sinking and accuses Seoul of goading it into launching the later artillery attack.

An attempt at reconciliation last month came to nothing after low-level military talks between the two sides collapsed.