Yonhap News Agency, quoting the South Korean Defense Ministry, said North Korea launch the rocket at 9:51 a.m. local time.
The report quoted the Japanese government that some debris from the rocket fell into waters off the Philippines at 10:05 a.m. after passing over Okinawa.
The isolated Communist country had earlier extended the launch window until Dec. 29 from its earlier Dec. 10-22 period. The North has maintained the launch was designed to put an Earth satellite in space, but critics, including the United States, suspect it was designed to test a ballistic missile capable of carrying nuclear weapons.
A similar test in April failed, earning North Korea strong condemnation from the United Nations.
A South Korean military official had told Yonhap Tuesday the North had removed its UNH-3 rocket from the launch pad in Dongchang-Ri because of a "technical deficiency."
Min Kyung-joo, the chief of South Korea's Naro Space Center, had said it was clearly a major problem. An official told Yonhap the problem appeared to have been in the direction control system.