The initiative follows an inter-Korean agreement reached earlier this week that committed both sides to organise a reunion sometime around the Chuseok harvest festival holiday, which falls on September 27.
An official from the South's Unification Ministry said the North had accepted the Seoul's proposal for initial talks on September 7 at the border truce village of Panmunjom.
The last family reunion was held at a North Korean mountain resort in February 2014, and was the first such event for more than three years.
Most died without having a chance to see or hear from their families on the other side of the border, across which all civilian communication is banned.
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About 66,000 South Koreans -- 12 percent of them aged over 90 -- are on the waiting list for an eventual reunion, but only several hundred can be chosen each time.
The reunion programme began in earnest after a historic North-South summit in 2000, but the waiting list has always been far larger than the numbers that could be accommodated.
The two sides have organised reunions in the past, only for the North to cancel at the last minute, citing some perceived insult or display of aggression from the South.
Given the time it takes to organise a reunion, the event is unlikely to be held before October.