South Korea on Tuesday agreed to Pyongyang's offer to hold joint research into volcanic activity in the peninsula's highest mountain, suggesting officials meet next week in a rare sign of cooperation.

The South's proposal of talks follows heightened concerns about activity at Mount Paekdu since a massive quake-tsunami engulfed the Japanese coast on March 11, killing at least 8,805 people and leaving 12,664 missing.

Seoul's unification ministry, which handles cross-border affairs, in a letter accepted an offer from North Korea's earthquake bureau to conduct research at the mountain on the border between the North and China.

Pyongyang's offer came six days after the Japan disaster.

"We said in the letter we agreed to the need for inter-Korea cooperation in studying volcanic activity in Mount Paekdu and proposed a meeting of experts...on March 29," the South's ministry said.

Since its last eruption in 1903, the 2,740-metre (8,990-foot) mountain has been inactive. But experts say it may have an active core, citing topographical signs and satellite images.

The mountain contains nearly one billion tonnes of water, which could deluge surrounding areas and spark chaos in North Korea.

Cross-border ties have been icy since the South accused the North of torpedoing a warship in March 2010 with the loss of 46 lives. Pyongyang denies the charge, but went on to shell a South Korean island -- killing four people -- in November.

South Korea on March 17 rejected an offer from North Korea to discuss its new nuclear programme and return to six-party disarmament talks, saying its neighbour must first show peaceful intentions.