Director Imtiaz Ali has been asked to remove or pixelate a slogan supporting Tibetan independence, reports Mumbai Mirror.
"There aren't too many Bollywood films that would dare to take a stand on a sensitive political issue like Tibet. Rockstar does. The censor board has asked for its removal," said a source.
The film shows the flag at a rock concert Ranbir Kapoor performs at in Mcleodganj, the home of the Tibetan government in exile.
Rock music as a genre has a strong following amongst the Tibetan community in India, as well as in Bangalore and the North Eastern region of the country.
Kapoor previously learnt how to milk a cow for his part in the movie. The actor also filmed key scenes in Mumbai's red light district.
Ali has confirmed that the plot of his next film project will focus on the Tibetan independence movement.
"I'm working on the project. And once I am free from Rockstar I will go to McLeodganj to complete the groundwork," he commented.
In 2007, Saif Ali Khan faced criticism for carrying the Olympic Torch prior to the Beijing Olympics, though defended his decision to run, by saying that he was "highlighting the cause of Tibet".
The actor's sister, Rang De Basanti star Soha Ali Khan, pulled out of the planned event at the last minute.
Eros International's Rockstar releases November 11.
Watch the trailer for Rockstar below: