Polanski quits directing 'Pompeii' movie
The move has meant that the future of the production could be in jeopardy over fears that an actors' strike could stop filming all together.
Contracts for the Screen Actors Guild and the Directors Guild of America are due to expire on June 30 next year, but filming has been scheduled in for Southern Italy in August 2008.
Producer Robert Benmussa suggested that if the union dispute is resolved by next February there is a chance that Polanski will come back on board, but he admitted: "I've very little hope of that."
Polanski said of his decision: "I put a lot of work and energy into the development of Pompeii so it is not without regret that I have to decline my further involvement."
Millions have already been spent on the epic film but Benmussa, as well as producer Alain Sarde and Summit International, insisted that they are still committed to carrying out the project.
Benmussa said: "I don't know what we are going to do yet. If Polanski is no longer directing, we'll have to completely remount the project. Distributors will also have their liberty to pull out of the film.
"We still have the book rights, we still have a scenario and a very strong subject that people all over the world are interested in. This is a temporary problem that we have to resolve."