Six members of a South Korean civic group have left for North Korea to check whether its food aid is being delivered to needy children and not diverted to the military, officials said Wednesday.

The Korean Council for Reconciliation and Cooperation, which so far has delivered 600 tonnes of flour in two shipments, said its officials would visit day care centres and kindergartens in the southwestern city of Sariwon from Wednesday to Saturday.

The group plans to send a total 2,500 tonnes of flour to the isolated North by the end of August.

"The officials will visit several institutions to check if the food has been distributed in line with the distribution plan document," said Lee Jong-Joo, spokeswoman for Seoul's unification ministry, which is responsible for authorising all cross-border exchanges.

Seoul officials believe flour can easily be diverted to the North's powerful military unless deliveries are tracked.

Lee said the Seoul government had asked the private group to strengthen monitoring of the flour shipments "considering the nature of the item", and its members would continually visit the communist North.

The South in 2008 stopped an annual government shipment of 400,000 tonnes of rice to its impoverished neighbour as cross-border relations soured.

Authorities allowed some civilian groups to keep sending aid, but suspended approval for flour shipments after the North's shelling of a border island last November that killed four South Koreans.

The reconciliation council's initial shipment on July 26 was the first flour aid since the suspension.

The North has relied on international aid to help feed its people since a famine in the 1990s killed hundreds of thousands. This year it asked the United States and other nations for food aid as international assistance dwindled due to concern over its nuclear programmes.

United Nations agencies estimate that some six million people there are in urgent need of food.

UN secretary-general Ban Ki-moon, quoted by Yonhap news agency from New York, appealed Tuesday for more food help for the North.

"The UN views North Korea's food conditions as being at a serious level and hopes for the international community's active contributions," he said.