Actor Jon Voight has launched an explosive attack on Barack Obama, calling the U.S. President a "false prophet".

The Midnight Cowboy star hosted a fundraiser for the U.S. Republican Party in Washington, D.C. on Monday, where he took to the stage to deliver a fiery speech criticising Obama, who became President in January.

Voight told the assembled audience that the Democrat had fooled people into voting him into the White House by promising change.

But the veteran actor, whose daughter Angelina Jolie has publicly praised Obama in the past, remained adamant the President's administration has thus far been a failure.

He said, "Are we supposed to be sitting and waiting, watching for the possibility of a new Holocaust? Who's going to take the responsibility to keep America, I mean Israel, safe? I'll tell you why this really scares the hell out of me. Everything Obama has recommended has turned out to be disastrous.

"Obama really thinks he is a soft-spoken Julius Caesar. He think he's going to conquer the world with his soft-spoken sweet talk and really think he's going to bring all of the enemies of the world into a little playground, where they'll swing each other back and forth."

The 70 year old went on to call for the Republican party to rally together to resume power: "We and we alone are the right frame of mind to free this nation from this Obama oppression. Let's give thanks to (Republicans) for not giving up and staying the course to bring an end to this false prophet, Obama."