South Korean football club FC Seoul have apologised for using apparent sex dolls instead of standard mannequins to fill seats during a K League match against Gwangju.

The top-flight side were playing a behind-closed-doors game due to ongoing coronavirus measures and decided they would use dolls in order to create the illusion of a crowd and improve the playing atmosphere.

But viewers were quick to notice that the 25 female and five male mannequins looked more like sex toys than spectators.

Some dolls were even shown holding advertisements for sex websites, despite pornography being banned in South Korea.

"Just look at their breasts, they were four times bigger than those of normal mannequins," wrote one fan while another added that it was ‘so obvious’ they were sex dolls.

The club has since issued a statement informing fans that the dolls were not bought under the title of ‘adult products’ but apologised for the oversight.

"We wanted to bring some fun elements to the no-fans game and give the message that we can overcome this difficult period," it said.

"We had confirmed that the mannequins were made as if they were real but had nothing to do with adult products.

"But the problem was we failed to make detailed checks, which is our fault without a doubt."

A number of the dolls were dressed in the club's black and red kit while others were holding signs supporting the team.

Dalcom, who manufactured the mannequins, also produce X-rated toys and club official Lee Ji-hoon admitted to the BBC  that he should have done a more thorough background check before agreeing to use their products.

The incident comes as a setback for the K League, which is currently one of the only soccer leagues to have re-started amid the coronavirus pandemic and has therefore been enjoying increased publicity with broadcasters from 10 countries buying rights for the season.

Sports Seoul website were worried over the international impact the controversy might have.

 “There are concerns this will bring international disgrace," they said.