The UN special rapporteur on North Korea's human rights situation has renewed calls for North Korea to release political prisoners, saying that Pyongyang should "follow suit" after Venezuela recently let such people free.

Tomas Ojea Quintana made the appeal in a tweet following Venezuelan President Nicolas Maduro's decision earlier this week to pardon over 100 political prisoners and activists who had been exiled or imprisoned.

"The Democratic People's Republic of Korea should follow suit.

Once again, I urge the Government to release political prisoners, specially older, ill and undernourished, persons with disabilities, children, pregnant and lactating mothers and nursing parents," he said, using the North's official name.

North Korea has long been labeled one of the worst human rights violators as it does not tolerate dissent, holds hundreds of thousands of people in political prison camps and keeps tight control over outside information.

The North, however, has bristled at such criticism, calling it a US-led attempt to topple its regime.

According to a report released by Amnesty International in January, the North is presumed to be running four political prisons where torture and various serious human rights violations are being committed.

Meanwhile, an official of Seoul's unification ministry handling inter-Korean affairs said that South Korea continues to make efforts to achieve tangible improvement in the human rights situation in North Korea as it marks the anniversary of the North Korean Human Rights Act that went into effect in 2016.

The official added that efforts are being made to resolve humanitarian issues related to families separated by the 1950-53 Korean War, prisoners of war and people abducted by North Korea. (Yonhap)