Top North Korean military official Hwang Pyong-so has made his first public appearance in about three weeks, the North's media showed Thursday, amid speculation that he went abroad for medical treatment.

The 75-year-old director of the general political bureau of the Korean People's Army has accompanied the North's leader Kim Jong-un on his visit to a tree nursery unit under the military, according to the Korean Central News Agency.

It marked the first time that Hwang has shown up at a major public event since he delivered a eulogy at a state funeral for a military marshal in early November.

Hwang is believed to have returned to Pyongyang after recently visiting China to get surgery on his backbone, according to a source familiar to North Korean affairs.

The sudden disappearance of North Korean officials from the public eye is usually viewed by outside analysts as being linked to a possible purge or punishment.

But experts have downplayed speculation that he might have been disgraced, citing his firm position in the North.

Hwang's status in the North is widely seen as relatively stable, as he was recently granted the title of the country's "hero" in recognition of his role in ending South Korea's resumption of an anti-Pyongyang loudspeaker campaign.

The North's leader has been wielding his power in a brutal way by purging or executing senior officials since he took office in late 2011, following the sudden death of his father Kim Jong-il.

The KCNA, meanwhile, confirmed the title of Ma Won-chun, who was once demoted due to his mishandling of a new airport project, as director of the design department at the North's powerful National Defense Commission.

Kim Jong-un is believed to have purged Ma, who spearheaded the construction of a new airport terminal in Pyongyang which opened in July. Ma was blamed for the terminal's failure to boost national character.

He returned to the public eye for the first time in about one year in October.

Under Kim's regime, Ma has been leading major construction projects such as the Masikryong Ski Resort on the North's east coast. (Yonhap)