The Perks of Being a Wallflower and Harry Potter star is in talks to appear in Aronofsky's biblical epic, reports Deadline.
Watson is eyeing the part of Ila, a character who develops a close relationship with Shem, one of Noah's sons.
Variety additionally reports that the role was originally offered to Dakota Fanning, who had to decline due to a scheduling conflict.
Jennifer Connelly and Julianne Moore have both been linked to the role of Noah's wife, while Liev Schreiber is also rumoured to be in contention to play the film's antagonist.
Russell Crowe will appear in the title role, while Douglas Booth (Romeo and Juliet) and Watson's Perks of Being a Wallflower co-star Logan Lerman will play Noah's sons.
Black Swan director Aronofsky has also written the script for the movie with Ari Handel. Oscar-nominated screenwriter John Logan (Gladiator, Hugo) was responsible for recent revisions.
Filming on Noah is due to begin next month in New York and Iceland. A US release date has been pencilled in for March 28, 2014.
Watch Emma Watson and Logan Lerman in the trailer for The Perks of Being a Wallflower below: