Co-star Harold Ramis had previously said that the 59-year-old would reprise his role as Dr Peter Venkman for the third instalment, which is being written by Gene Stupnitsky and Lee Eisenberg.
However, Murray told AbsoluteRadio that he does not want to commit to the film until he reads the screenplay.
He said: "Well, I don't know. I'll believe it when I see it. I saw a guy talking about the end of the world a couple of years ago, and I haven't seen that either.
"So I'm not going to be believe the Ghostbusters story until I see the script."
He added: "Well, I don't want to do it yet. There's still no script, it's just a bunch of talk. It's just a wish list for someone. Until there is a really good script, I'll stay home. It has to be a serious script before I leave the house.
"I'm not going to make one [movie] just to make another one. We made a second one, and it was okay, but it wasn't as good as the first one."
Sigourney Weaver, Murray's co-star in the first two films, confirmed in June that she will not return to the franchise.
Murray can currently be heard as the voice of Badger in Fantastic Mr Fox, which opens in UK cinemas on October 23 and in the US on November 25.