South Korea's top court has ruled in favor of a Korean-American singer who was banned from entering South Korea, a decision that may help him visit the country for the first time in 18 years.

The Supreme Court on Thursday upheld a lower court's decision that was handed down in favor of Steve Yoo, better known as Yoo Seung-jun here, in a lawsuit against South Korea's diplomatic mission in Los Angeles for refusing to grant him a visa.

Yoo, 43, had been banned from entering South Korea since 2002, when he became the subject of public outcry after giving up his South Korean citizenship, which critics claimed was aimed at dodging military service.

After botched attempts to enter the country, he filed a lawsuit against the South Korean Consulate General in Los Angeles in October 2015 for refusing to grant him a visa. Yoo reportedly applied for an F-4 visa, which is usually issued to Koreans living overseas.

In 2017, the Seoul High Court ruled the refusal was appropriate, but the Supreme Court in July 2019 ordered the same court to revisit the ruling, saying it violated due administrative procedure. In November last year, the appeals court ruled in favor of Yoo.

But the top court's decision does not mean that Yoo's entrance to South Korea will be automatically permitted as the main contentious point in the lawsuit was whether the visa refusal was proper.

Yoo is expected to apply for a visa again, but there is the possibility that the Korean consulate general in Los Angeles may reject the visa issuance, citing other reasons.

"We expect an appropriate decision that will be commensurate with the purpose of the ruling as the top court handed down the same decision twice," a legal representative of Yoo said.

South Korea's foreign ministry said if Yoo applies for a visa, it will decide on whether to issue it after consulting with related agencies

"The government will decide on whether to grant the plaintiff a visa through the legitimate exercise of discretionary authority," the ministry said.

Yoo had been a mega-hit singer until the citizenship issue sparked public fury in a country where mandatory military service is a sensitive issue.

By law, all able-bodied men have to serve in the armed forces for around two years before the age of 38. (Yonhap)