North and South Korea have opened new military hotlines  to help facilitate border crossings, the latest sign of renewing co-operation between the countries.

Military officials from the two countries used the fibre-optic cables to help facilitate the travel of 330 South Koreans heading to an industrial complex in the North, Lee Jong-joo, a unification ministry
spokeswoman said on Wednesday.

South Korea sent fiber-optic cables and other equipment to the North to help its neighbor modernise its military hotlines, Lee said.

The at the North Korean border town of Kaesong, which combines South Korean capital and technology with cheap North Korean labour, is the most prominent symbol of inter-Korean co-operation.

About 110 South Korean factories at Kaesong employ around 40,000 North Korean workers.

"The two Koreas will be able to exchange information between cross-border personnel swiftly and more stably," a government official told the Yonhap news agency.

Humanitarian aid

The new hotlines replaced outdated copper cable hotlines that will remain as spare lines.

The hotline renovations, agreed upon in 2007, were put on hold after inter-Korean relations soured following the inauguration of Lee Myung-bak, the conservative South Korean president who has maintained a tough policy towards the North.

However, earlier this month, South Korea sent H1N1 medication to North Korea, its first humanitarian aid to the North since Lee's appointment.

The North made a rare expression of gratitude for the aid.

North Korea also resumed dialogue with the US after the country's nuclear envoy visited the country earlier this month in a bid to persuade the North to return to stalled international nuclear disarmament talks.

The two Koreas are still technically at war because their 1950-53 Korean War ended with an armistice, not a peace treaty.