The Constitutional Court opened public hearings to rule on whether the country's anti-sex trade law is constitutional.
Opponents of the law say sexual acts between adults, made without exploitation or coercion, should be left to individuals' sexual self-determination, and the state should not intervene in such acts. In contrast, proponents have expressed concerns that abolishing the law could increase the number of prostitutes and create bigger social problems.
The court is expected to make a ruling this year after holding several rounds of hearings.
Kim Kang-ja, a former chief at the Jongam Police Station who led many crackdowns on the industry in the 2000s, said her operations only worsened the situation of sex workers, many of whom were undereducated and could not find anything else to do for living.
"Without a proper social system in which they can feed and educate themselves, the crackdowns failed to eradicate prostitution," she said. "The current system pushes sex workers to places where their rights are largely abused by pimps or buyers."
For those who have nothing else to do for living, she said, prostitution should be legalized in limited areas.
Korea University Law School Professor Park Kyung-shin echoed her views.
"Women's rights activists say that sex workers are the victims of crimes. But that doesn't make sense, if their actions are voluntary, which is actually the case for many," he said. "To justify criminalizing sex buyers, the government must set up the environment where everyone can tell who the voluntary workers are."
Lawyer Choi Hyun-hee disagreed. She said prostitution could lead many adolescents into the sex business.
She also said that it would cause more human trafficking and sex crimes, while sex workers' rights will still be violated in many other forms.
"Because it a human rights issue, prostitution cannot be justified only by people's right to have sex or make choices," she said.
In 2013, the Seoul Northern District Court asked for a constitutional judgment on the anti-sex trade law, which stipulates a punishment of up to one year or a fine of up to 3 million won for those who sell or buy sex.
Ahead of the arguments at the Constitutional Court, a group of prostitutes turned in a petition with 882 signatures to the court, claiming that the anti-sex trade law was no good for them or society.
"There are no victims as long as prostitution is not forced or extorted," they said in a statement. "We don't believe that preventing prostitution is more ethical, given that shady sex trades possess more risks to sex workers."