SEOUL (AFP) - North Korea has sacked its commerce minister, according to state-run media on Saturday, as its young leader Kim Jong Un apparently seeks to sideline supporters of his once-powerful uncle who was executed last year.

North Korea's radio broadcaster Pyongyang Broadcasting Station said that new Commerce Minister Kim Kyong Nam took part in a food festival marking the birth anniversary of the country's founder Kim Il Sung.

It was the first time that North Korean media introduced him as commerce minister, but it was likely that his predecessor Ri Song Ho was replaced last month in a pre-determined election for the rubber-stamp parliament, Yonhap news agency said.

Kim Kyong Nam was one of the 687 approved candidates elected unopposed in an exercise held every five years that provides a rare glimpse into power shifts within the secretive regime.

Ri, who took office in 2012, failed to get re-elected to the Supreme People's Assembly.

It remains unclear why Ri was replaced but his ouster comes as Pyongyang has reportedly been purging officials linked to Jang Song Thaek, once the North's unofficial number two and Kim's political mentor.

Jang was executed in December on an array of charges including treason and corruption, marking the biggest political upheaval since the young ruler took power after the death of his father and the former leader, Kim Jong Il, in 2011.

Ri is the latest North Korean cabinet member to be sacked since Jang's execution. North Korea reportedly replaced its mining minister and metal industry minister in January.

South Korea's Unification Minister Ryoo Kihl Jae said in December that North Korea was purging officials who had been close to Jang.

The purge however appears to be targeting a relatively small circle of officials, Ryoo said, rejecting speculation of a sweeping clear-out of party and military ranks.

Seoul's spy chief also said in December that two of Jang's associates had been executed, while Pyongyang reportedly recalled some diplomats or trade officials overseas who were believed to have been close to Jang.