South Korea's unification minister has suggested that North Korea could be preparing to continue Kim family rule into a fourth-generation with the daughter of its leader Kim Jong Un as next in line.

Kim Yung-ho told foreign correspondents in Seoul on Tuesday that the daughter had appeared in North Korean media 19 times, with 16 of her appearances related to military events.

He noted that she was saluted and spoken to by senior military officials who went down on their knees to show respect.

Kim said the possibility of the daughter becoming a successor cannot be ruled out. He indicated that Pyongyang may be putting her in the spotlight early to lay the groundwork for succession.

The unification minister also noted that the North is concerned about its system being undermined by the inflow of South Korean pop culture, such as TV dramas and music.

Kim said he believes Pyongyang's resolve for a hereditary succession is aimed at solidifying internal unity.