The actress played a supporting role as the warrior goddess in the first film alongside Chris Hemsworth, Natalie Portman and Tom Hiddleston.
Alexander said that while she was not officially signed on to the sequel, she has had "a few discussions" about reprising her role.
"I'm a comic book nerd at heart, so I'd like to see the relationship between Thor and Sif progress," she told MTV News.
"Whether or not they do that, we're not sure yet. We'll see. I think that element will be in there, but I don't know how much."
Alexander also hinted at a possible appearance in Joss Whedon's Avengers movie.
"I can't tell you," she said when asked if she would feature in the ensemble film.
"Sometimes you never know. It'll be funny - they'll call you and they'll do a post-credits scene and you go, 'Oh, so everything I said in interviews is completely wrong'. So you never know!"
Thor 2 is currently being rewritten by Saving Private Ryan screenwriter Robert Rodat.
Watch the Thor trailer below: