South Korean President Park Geun-hye had called for the reunions to restart in conjunction with Lunar New Year's Day on Jan. 31, one of the biggest holiday on the Korean peninsula, Yonhap news agency reported.
"Can the separated families and relatives have reunions in peace amid gunfire?" Pyongyang's Committee for the Peaceful Reunification of the Fatherland asked in a message to the South's reunification ministry, rejecting Park's proposal.
The committee noted Seoul recently held military drills and plans joint military exercises with the United States this spring.
However, the committee said the two Koreas could meet in "a good season" if there is "no other thing happening on the South's side and if the South's side has intent to discuss the proposals of our side."
The statement did not mention specific proposals. South Korean officials said Pyongyang may have referred to North Korea's demands for the South to resume tours of Mount Kumgang, a mountain resort on the communist country's east coast, and for Seoul to end annual military exercises with the United States.
South Korea ended tours to Mount Kumgang in 2008 after a North Korean guard shot and killed a South Korean tourist.
The countries agreed to hold family reunions at Kumgang last year but North Korea canceled them at the last minute.