[Israel TV interviewed former officials who said they had taken part in the talks, with the knowledge of the government.]
"No one in the government was involved in this matter," Olmert told reporters in northern Israel. "It was a private initiative on the part of an individual who spoke with himself. From what I read, his interlocutor was an eccentric from the U.S., someone not serious or dignified."
The Syrian Foreign Ministry also rejected the report.
"No negotiations took place, the Haaretz report is completely false," a Syrian Foreign Ministry official said in Damascus.
Official Israeli response to the report was more tentative.
"This is the first we have heard of the talks, we have never sanctioned anybody to speak to the Syrians and the prime minister first learned of these conversations through the newspaper report this morning," said Olmert's spokeswoman Miri Eisin.
An unnamed senior cabinet minister was quoted Tuesday as saying that there were no contacts between the two nations, and that the story was "a bluff."
"We don't know about this, and if this had happened, we would have known about it," Israel Radio quoted the minister as saying. "This is not serious. It's possible that there were contacts on the level of academics, it's possible that there were reports to officials on a low level. But it did not reach higher than that."
The minister dismissed the report as a "bluff," the radio said.
Former foreign minister Silvan Shalom said that he first learned of the talks by reading Tuesday's paper. He said the last contact Israel had with a Syrian representative was in 2003.
Dr. Alon Liel, a former director general at the Foreign Ministry, who took part in all the meetings, was quoted as saying that he had not acted the representative of anyone. Liel further declined to state whom he had informed of the meetings.
The radio quoted unnamed senior Israeli officials as stating that Israel is not holding contacts with Syria.
The officials referred to the sensitivity of the issue, in view of the opposition of Washington, Israel's main ally, to negotiations with the regime of Syrian President Bashar Assad.
"Syria is trying to topple the Siniora government in Lebanon, a government which the United States is trying to aid," the radio quoted one official as saying. "Syria streams terror elements to Iraq, where they operate against the United States military, Syria fosters [Damascus-based Hamas leader] Khaled Meshal, it transfers arms to Hezbollah, hosts headquarters of terror organizations, supports Hamas, and, in general, undermines any attempt to reach a [peace] agreement
A figure described as a very senior official in the office of then-prime minister Ariel Sharon was quoted as saying that "there was no reports to Sharon, there were no reports to his office, there was no connection between Sharon and Alon Liel, this never happened."
"This is absolute nonsense."