South Korea has repatriated nearly 200 North Koreans who came to the South via the sea border since 2010 but two fishermen sent back in 2019 were deported against their will, data from Seoul's Unification Ministry showed on Friday.

The rare data from the ministry in charge of inter-Korea affairs emerged after prosecutors reopened an investigation into the fishermen's case amid a public outcry over the previous government of President Moon Jae-in's handling of the their constitutional and human rights.

It showed that a total of 276 North Koreans had arrived in the South on 67 occasions since 2010, whether they went adrift at sea or were detained after violating the border. Of them, 194 returned home while 82 defected to the South, and only the two fishermen were listed as "expelled."

South Korean authorities usually question all North Koreans detained or found in the South about how and why they crossed the border, and repatriate anyone who wishes to go back.

Officials who served under Moon said the fishermen did not deserve South Korean protection and resettlement support, calling them "grotesque criminals" who had killed 16 other crewmen in a fight aboard a ship before crossing the border.

But legal experts and human rights specialists condemned the deportation, saying the Moon administration violated the men's rights by sidestepping an obligation for its justice system to deal with them.

The country's constitution defines all North Koreans as South Korean citizens.

President Yoon Suk-yeol's office on Wednesday criticised the decision as a potential "crime against humanity," after the Unification Ministry unveiled photos of the two fishermen being forcibly dragged across the border, with their hands tied and eyes covered.

Prosecutors have imposed a travel ban on two former intelligence chiefs involved in the case, the JoongAng Ilbo newspaper reported on Friday.

"The government has no right to decide the fishermen are criminals as they were not prosecuted nor found guilty by the South Korean judiciary," Jhe Seong-ho, a professor at Chung-Ang University's law school, told a seminar hosted by defector-turned-lawmaker Tae Young-ho.