In the message, the caller says, referring to a potential subpoena: “There is not a goddamn thing your phony, psycho, piece-of-shit son can do about it. Bernie, your phony loans are about to catch up with you. You will be forced to tell the truth and the fact that your son’s a pathological liar will be known to all.”

Mr. Stone, 55, said the number from which the call was alleged to have been made was indeed his, and that it was also shared by a Florida law firm for which he does public relations work, Rothstein Rosenfeldt Adler. But he denied that he made the call or that it was his voice on the message.

He said his apartment building on Central Park South is owned by H. Dale Hemmerdinger, a fund-raiser for Mr. Spitzer who is the governor’s nominee to be chairman of the Metropolitan Transportation Authority, and suggested that allies of the governor might have given access to his apartment to someone who made the threatening call. An official at Mr. Hemmerdinger’s company said she was not prepared to comment.

Mr. Stone said: “They have unfettered access to my apartment. I am on television constantly. As Gore Vidal said, never pass up the chance to have sex or be on television. Putting together a voice tape that sounds like me wouldn’t be hard to do.”

Mr. Stone said he could not remember where he was on the date of the call and had no specific evidence that his apartment had been entered without authorization. But he said he believed that things have been missing from his apartment recently.

Mr. Winner also noted that technology is available that makes it possible to mimic another person’s phone number on a caller identification machine.

Mr. Stone is known as an aggressive strategist, having once, while still a teenager, recruited a mole to infiltrate the 1972 presidential campaign of George S. McGovern. He worked for Ronald Reagan in 1980 and 1984 and went to Florida in 2000 to help George W. Bush win the recount. On his Web site, Mr. Stone claims to know “first hand the gritty underside of American politics.”