Squid Game actor O Yeong-su has been indicted on charges of sexual misconduct after he allegedly touched a woman inappropriately.

Yeong-su, 78, was indicted by South Korean prosecutors on Thursday after a complaint by a woman claiming the Golden Globe winner touched her inappropriately in mid-2017.

The alleged victim had filed a complaint to the police in December last year, but they closed the case in April without filing charges against Yeong-su, reported Yonhap news agency. 

But the prosecutor's office in Suwon, south of the capital of Seoul, reopened the case and investigated the allegations, which Yeong-su has consistently denied.

The actor has previously spoken about the allegations, telling local media last year that he had 'held hands with the woman to show the way around a lake'.

Yeong-su apologised to the alleged victim last year, but insisted he'd done so because the woman said 'she wouldn't make a fuss about it' and stressed that an apology 'doesn't mean that I admit the charges'.

Yeong-su won South Korea's first Golden Globe award in January for his role as Oh Il-name in the Netflix hit Squid Game. 

South Korean President Moon Jae-in congratulated Yeong-su and the drama's crew, saying 'Squid Game' gave hope for humanity despite its gloomy depiction of society.

'Squid Game', in which cash-strapped contestants play childhood games with deadly consequences in a bid to win 45.6 billion won, became a worldwide sensation and Netflix's biggest original series launch.

The dystopian drama has inspired countless real world recreations and social media memes in South Korea, including his use of the term 'kkanbu', which roughly translates as 'friend', propelling his popularity as a hippy 'kkanbu grandpa'.

Born in 1944 in what is now a North Korean border town of Kaepung, O is regarded as one of the greatest stage actors in South Korea, appearing in more than 200 stage productions since 1963 and winning a number of major awards.

He has also played many charismatic supporting characters in film and television, including in 'Spring, Summer, Fall, Winter… and Spring' released in 2003 by late award-winning director Kim Ki-duk.

O's portrayals of a Buddhist monk in that 2003 movie and others won him the nickname 'monk actor' and several television commercials.

He said during a TV appearance in October that he had decided to join 'Squid Game' out of appreciation for the director's insight over social irregularities.

'Our society goes by as if only No. 1 survives. No. 2 lost to No. 1, but beat No. 3. After all, everybody is a winner,' he said then.