The actor and former Governor of California revealed during the Expendables 2 Comic-Con panel on Thursday (July 12) that the project is in development and that Twins director Ivan Reitman and Universal Pictures have shown interest.
Schwarzenegger added that he is looking forward to finding the right writer for the project, which reportedly has the working title of Triplets.
Twins was released in 1988, starring Schwarzenegger and Danny DeVito as fraternal twins who were separated at birth and reunited as adults.
Schwarzenegger was previously quoted as saying that he would "love to do another Twins", while DeVito has said that he hopes the sequel will be filmed next year.
It was originally understood that Reitman would produce rather than direct any Twins sequel, while Eddie Murphy has also been linked to the movie.
Comic-Con International runs until July 15 at the San Diego Convention Centre.
Watch Arnold Schwarzenegger in a trailer for The Expendables 2 below: