Singapore's film censorship body has given the highest-possible age restriction to critically-acclaimed Love, Simon, despite it featuring no sex scenes or violence.

The coming-of-age romantic comedy follows the love story of Simon Spier who has fallen in love online and is yet to tell his friends and family he is gay and is directed by Greg Berlanti.

The film is listed as a 12A in the UK and PG-13 in the United States.

A petition started by local activist Thasha Monique Dharmendra has garnered more than more than 13,000 signatures by monday.

"I realised that the movie Love, Simon has been rated R21 by the Media Development Authority of Singapore which I think is ridiculous as there is no sexual intercourse or violence involved," Dharmendra wrote on the petition's page

"It's just a harmless coming of age movie where the main character happens to be gay. A young Singaporean teen struggling with their sexuality might find themself relating and finding comfort in this movie."

Watch the trailer below: