Stenberg portrays Rue, the brave little girl who nurses Katniss (Jennifer Lawrence) back to health at a key point in the film.
As E! Online notes, contrary to these complaints, Collins actually depicts Rue as having "dark brown skin and eyes." Cinna's race is never explicitly mentioned.
Many of the tweets are peppered with racial slurs.
One particularly shocking tweet reads: "Sense when has Rue been a nigger."
Another alluding to Rue's untimely death reads: "call me racist but when i found out rue was black her death wasn't as sad #ihatemyself."
A few commentators struck back at the remarks using humor.
"I hear that Donald Trump is trying to prove that Rue wasn't even BORN in Panem," one tweeter wrote, with a nod to the "Birther" controversy that "The Apprentice" star kicked up over Barack Obama's American citizenship.
The comments came to light thanks to a Tumblr page maintained by a fan of Collins' young adult novels.
The page collects tweets that the author says expose other alleged fans' ignorance of "The Hunger Games."