SEOUL - Tens of thousands of lovelorn South Koreans are set to take part in a "battle of the singles" on Christmas Eve - a mass dating event triggered by an innocuous query posted on Facebook last month.

More than 36,000 people have signed up for the event in a park in central Seoul since two young men jokingly floated the idea on the social networking site and met with an overwhelming response.

"We only asked 'What do you plan to do on Christmas Eve?' and people started to leave thousands of comments that they were single and miserable and had nothing to do," Justin Chanwook Jang, one of the two organisers, told AFP.

"So we suggested this idea to help lonely singles find love on Christmas Eve ... we never imagined it would grow this big," said 29-year-old Jang, who plans to participate himself.

Some businesses have decided to enter into the spirit of things by allowing single employees the day off on Christmas Eve which falls on Monday, and around 200 firms have offered to sponsor the event.

The rules of "the battle" are simple.

Women must dress in red and men in white and all gather at the park, which sits on an island in the Han River that bisects the capital.

The two groups will stand facing each other a few metres apart until the event starts at 3:00pm (2pm local time) - then run towards a potential date and grab his or her hands.

Those who manage to get a date are encouraged to post photos taken with their new partners on the event's Facebook page.

It remains to be seen how many of those who signed up will actually attend, but Jang is confident.

"I'm witnessing how social networking sites can help a tiny idea grow so big and so quickly ... it's overwhelming," he said, adding that more than 200 people had volunteered to act as stewards.

When it became clear just how many people might turn up, the organisers informed the police and asked them to help monitor the event.

News of the "battle" has been publicised on major Korean Internet sites and Twitter, with a flood of postings expressing both excitement, scepticism and concern.

"This will be a scene we all must watch ... a horde of men chasing after women to grab their hands and girls frantically running away," tweeted @ksmfilm.

"My only concern is white is not my colour. I'll pretend that I'm sick on that day so that I can leave work early," said one anonymous commentator.

One Facebook user warned that the mass event was an open invitation to sexual harassment and pickpockets.