The film, co-produced by Karan Johar, would have seen the two stars appear on screen together for the first time.
A source told Mumbai Mirror that here is "no fixed shooting schedule" for the picture, which is said to be stuck in the scripting stage.
However, production company Balaji Motion Pictures commented that rumours the project has been delayed are false.
Chief executive Tanuj Garg responded: "These rumours are totally unfounded. The script is awaiting completion, which is why we are marginally postponed. We will still release next year."
The romantic drama was to feature an "explosive" love-making scene between the pair.
In February, Hashmi said that odd couples are more "sexy" and create better chemistry on screen than more conventional pairings.