"If anyone was talking about legislating something and restricting Hollywood I would probably reach for my nearest Colt 45," he said.
Mr Lieberman, Al Gore's running-mate in the race for the White House, accused the film industry on Sunday of corrupting American culture, and hinted Washington could impose legal restrictions.
But Dreyfuss, whose films include Jaws, Close Encounters and Down and Out in Beverly Hills, said he would fight censorship with everything he had.
"If anyone was talking about legislating something and restricting Hollywood I would probably reach for my nearest Colt 45," he said.
Mr Lieberman, the Democratic vice-presidential candidate, said Washington could clamp down on studios if they refused to "draw some lines themselves".
"There is still too much violence, too much sex, too much incivility in entertainment, which makes it very difficult for parents, who are working so hard to give their kids values and discipline, to do so," he said.
Discussion
Speaking to Newsnight's Jeremy Vine at the Democratic convention, Dreyfuss welcomed calls for debates on Hollywood standards from all quarters.
But he added: "There's a huge difference between that discussion and the demand for legislation."
Dreyfuss said he wanted Hollywood to acknowledge the concerns expressed by polticians.
"I would like more taste, more common sense, more thoughtfulness.
"I would like a reach for the individual artist to areas other than those so easily gratified like sex and violence," he added.