The 78-year-old actor played elite secret agent Rollin Hand on the original TV series from 1966 to 1969. He said that he will not consider appearing in the film, following a bad experience that involved a rough draft script of the first movie.
He told MTV: "Unless it was a great part, which it probably isn't, it would probably be a cameo, a little joke, that wouldn't interest me at all.
"When they were working on an early incarnation of the first one - not the script they ultimately did - they wanted the entire team to be destroyed, done away with one at a time, and I was against that."
Landau added: "It was basically an action-adventure movie and not Mission. Mission was a mind game. The ideal mission was getting in and getting out without anyone ever knowing we were there.
"So the whole texture changed. Why volunteer to essentially have our characters commit suicide? I passed on it. I said, 'It's crazy to do this'. The script wasn't that good either!"
J.J. Abrams, who directed the third film in the franchise, recently stated that he would like original star Peter Graves to make an appearance in the project, which he is to produce with Tom Cruise.