Calling it a “terrible invasion of her privacy,” friends of hotel heiress Paris Hilton yesterday lambasted the owner of an Internet porn site who says he will broadcast a raunchy sex video of the Los Angeles-based celebutante.

“People are obsessed with Paris Hilton, and anytime they can find something that will show her in a debasing, derogatory way, they will,” PR woman Lizzie Grubman said of her longtime pal Paris, star of the upcoming “Green Acres”-style Fox reality show “The Simple Life.”

“Paris has a great heart, and she doesn’t deserve this.”

The video, supposedly filmed three years ago, shows Hilton, now 22, gallivanting in the Hollywood Hills home of Rick Solomon, who subsequently married and split from “90210” star Shannen Doherty.

Roger Vadocz, president of Internet porn company Marvad in Seattle, provided US Weekly with a three-minute clip showing two people he claims are Hilton and Solomon having sex. US Weekly news director Marc Malkin verified he has seen a “raunchy” snippet.

Vadocz said he plans to stream the footage on his soon-to-debut Web site. He did not return two calls yesterday.

Malkin reports in the current US Weekly that Solomon set out to prove the film exists after Hilton publicly denied it in August. A rep for Solomon, 33, said in reports published yesterday his client had nothing to do with the tape. Hilton has called Solomon “a complete liar.”

Friends call Hilton “a genius” who took bashings from the press and parlayed it into a successful – and lucrative – image rehabilitation. “It’s a terrible invasion of her privacy, but I don’t think it’s going to hurt her in the long run,” said pal Dori Cooperman, who has socialized with Hilton on both coasts and in St. Tropez.

Added another friend, who requested anonymity: “A sex video certainly didn’t hurt Pamela Anderson’s career. It appeals to people’s curiosity. So what’s the big deal?”

A rep for the Hilton family said Paris was in Australia and referred calls to a lawyer, who did not get back to Newsday by press time.