The son of the highest-profile South Korean to defect to the North has arrived in Pyongyang to permanently resettle there, according to the hermit nation's state media.

Key points: South Korea said Mr Choe did have its permission to visit the North

South Korea said Mr Choe did have its permission to visit the North Under South Korean law, people who secretly visit North Korea face up to 10 years in prison

Under South Korean law, people who secretly visit North Korea face up to 10 years in prison Since the end of the Korean War, more than 30,000 North Koreans have fled to the South

If confirmed, it would be an unusual case of a South Korean defecting to the impoverished, authoritarian North.

The 73-year-old's parents — one of whom was a government minister in the South — defected to North Korea in the 1980s, and reportedly told their son it was their dying wish that he follow their lead.

The state-run Uriminzokkiri website released footage showing a bespectacled Choe In-guk, wearing a beret, arriving at Pyongyang's International Airport on Saturday, saying he intended to permanently resettle in the North.

The two Koreas — split along the world's most heavily fortified border for about 70 years — bar their citizens from visiting each other's territory and exchanging phone calls, letters or emails without special permission.

Under a South Korean security law, people who secretly visit North Korea can face up to 10 years in prison.

South Korea's Unification Ministry said Seoul had not given Mr Choe special permission to go to North Korea.

Ministry spokesman Lee Sang-min told reporters on Monday authorities were trying to determine details about Mr Choe's travel.

Visits between the two Koreas illegal

Under a South Korean security law, people who secretly visit North Korea can face up to 10 years in prison. ( ABC: Brant Cumming )

North Korea has been struggling to revive its moribund economy and improve people's livelihoods, since the US decided against providing major sanctions relief until Pyongyang took significant steps toward nuclear disarmament.

Since the end of the 1950-53 Korean War, more than 30,000 North Koreans have fled to South Korea to avoid political repression and economic poverty.

South Koreans have occasionally defected to North Korea in the past, but it has become a rarity in recent years, especially since the North suffered a crippling famine in the mid-1990s that is estimated to have killed hundreds of thousands of people.

Of the small number of South Koreans who have tried to defect, most have been repatriated by North Korea, including two people last year.

Some analysts say North Korea accepted Mr Choe so it could use him as a propaganda tool to tell its citizens its system is superior to South Korea's.

Mr Choe's parents held high positions in the North

More than 30,000 North Koreans have fled to South Korea to avoid political repression and economic poverty. ( ABC News: Susan Kim )

Mr Choe is the son of former South Korean foreign minister Choe Dok-shin, who defected to North Korea with his wife in 1986, years after he was reportedly embroiled in a corruption scandal and political disputes with then-South Korean president Park Chung-hee. He died in 1989.

Before his 1986 defection, Choe Dok-shin had lived in the United States for about a decade and was a vocal critic of Mr Park, who ruled South Korea with an iron fist from 1961 to 1979.

He was previously Mr Park's foreign minister and ambassador in West Germany.

In North Korea, he was made vice chairman of the Committee for the Peaceful Reunification of the Fatherland, which deals with relations with South Korea, and chairman of the Central Committee of the Chondoist Chongu Party, a political group affiliated with a Korean native religion called "Chondo". He once headed the Chondo church in South Korea.

His wife, Ryu Mi Yong, also took a series of high-profile jobs, including membership in the presidium of the North's rubber-stamp parliament and chairwoman of the Central Committee of the Chondoist Chongu Party.

When she died at the age of 95 in 2016, a public funeral was held and her body was buried along with her husband's at Pyongyang's Patriotic Martyrs' Cemetery.

According to South Korea's Unification Ministry, Choe In-guk was allowed to make 12 authorised trips to North Korea since 2001 for events such as visiting his parents' graves and attending a death anniversary for his mother.

ABC/AP