North Korea will issue special pardons for prisoners to commemorate milestone birthdays of its two late leaders, state media said, in the first such dispensations in more than six years.

The pardons come as North Korea's new leader, Kim Jong-un, moves to solidify his power in the wake of his father Kim Jong-il's death last month. Believed to be in his late 20s, Kim Jong-un has already picked up a slew of prominent titles such as supreme commander of the military, with top officials publicly pledging their loyalty.

The pardons will start 1 February at the decree of the Presidium of the Supreme People's Assembly, the official Korean Central News Agency said in a dispatch. KCNA did not say what sorts of crimes would be pardoned or how many inmates would be freed.

The decision is meant to mark the 70th anniversary of the birth of Kim Jong-il in February, and the 100th anniversary of the birth of his father, North Korea founder Kim Il Sung, in April, KCNA said.

Those birthdays are the two most important holidays in North Korea. Pyongyang has promoted this year's Kim Il Sung centenary as a significant milestone in the country's history.

Kim Jong-un is believed to have turned 28 or 29 on Sunday but his birthday hasn't been designated as a national holiday yet.

North Korea occasionally marks significant holidays by granting amnesties. South Korea's Unification Ministry says North Korea last conducted such a special pardon in August 2005 to mark the 60th anniversary of Korea's liberation from Japan's colonial rule.

South Korea also marks special holidays with similar dispensations. On Tuesday, Seoul's Justice Ministry said it will pardon 955 prisoners on occasion of the Lunar New Year's Day later this month.