South Korea's presidential office on Monday expressed optimism that this week's inter-Korean summit will result in substantial progress in addressing the issue of families separated by the Korean War.

President Moon Jae-in plans to embark on a three-day trip to Pyongyang on Tuesday for his third summit with North Korean leader Kim Jong-un.

"There will be separate in-depth discussions on ways to resolve the pain of separated families," Moon's Chief of Staff Im Jong-seok told reporters during a briefing on the summit's agenda and key events.

"I expect we can deliver a good news because the North is also very positive."

He said that discussions are under way between two Koreas on the establishment of a permanent meeting facility, more frequent reunions, locating all registered separate relatives and video meetings.

Moon to arrive in Pyongyang at 10 am Tuesday 2018-09-17 09:12  |  North Korea
South and North Korea held family reunions last month at Mount Kumgang on the North's east coast in the latest reconciliatory measure since Moon and Kim held their first summit meeting in April. The reunions were the first since October 2015.

South Korea's Red Cross chief Park Kyung-seo earlier told reporters that the two Koreas discussed holding additional family reunions in October at the earliest.

The unification ministry later said that more consultations are necessary to produce an agreement.

According to government data, there are about 57,000 South Koreans wishing to meet family members in the North. Before last month's reunions, the two Koreas had held 20 rounds of such meetings since their first inter-Korean summit in 2000, mostly involving around 100 families from each side.

South Korea has pushed to hold family reunions with the North on a regular basis, but discussions were suspended over strained inter-Korean relations.

In their first summit in April, Moon and Kim agreed to work together in addressing humanitarian issues arising from decadeslong division of the Korean Peninsula.

The two countries technically remain at war as the 1950-53 Korean War ended with an armistice, not a peace treaty. (Yonhap)