"That (starting 'Munna Bhai 3' ) is an issue as Raju (Hirani) has to start the Sanjay Dutt biopic and it is getting pushed ahead," Arshad told PTI.
"Until and unless he (Hirani) decides he wants to do 'Munnabhai' part three first and then the Sanjay Dutt biopic... if that happens then we will go first," he said.
Hirani approached Ranbir to play Dutt's role in the biopic in November 2014 and the actor instantly gave his nod for the film.
The biopic was likely to go on floors this June. Now, the project is expected to go on floors next January and release during Christmas.
Since the "Munna Bhai" series is one of the most successful franchise, Arshad, 48, is quite excited about the third part.
"There is excitement for the film . There is no pressure.
I do my job, I don't take stress. The more stress you take the more worse you get. You hear a script, you like it, you give your best," he said.
There were rumours that Arshad and Dutt won't be seen in the third part of "Munna Bhai" series and younger actors will be playing the two iconic roles of Munnabhai and Circuit.
To this, Arshad said, "I don't think it will happen. I doubt."
"Munna Bhai MBBS" was a story of a goon named Munnabhai aka Murli Prasad Sharma (played by Dutt), who goes to a medical college, and his sidekick Circuit or Cirkeshwar (enacted by Arshad).
Its sequel "Lage Raho Munnabhai" showed Munna using the principles of Gandhian philosophy to bring about a change in the society.
Dutt had earlier served sentence in connection with the 1993 Mumbai serial blasts case. He came out of jail in February this year and Arshad had then met him.
"I met him after he was back home. We talked about lot of things which I can't say. We talked about what he went through (referring to jail term), his angst, on family, upcoming films...," he said.