Meir Dagan, a former Israeli military officer and director of Israel's Mossad national intelligence agency, told The Jerusalem Post he agreed with Yuval Diskin, director of the Israeli security agency Shabak, or Shin Bet.
Diskin said Friday Netanyahu and Defense Minister Ehud Barak were guided by "messianic" impulses and lied about the projected effectiveness of an Israeli strike on Iran.
"They are giving the sense that if Israel doesn't act, Iran will have nuclear weapons," Diskin said at a forum in Kfar Saba.
"This part of the sentence apparently has an element of truth," Diskin said.
"But in the second part of the sentence, they turn to the -- sorry for the expression -- the 'stupid public' or the layman public ... and tell them if Israel acts, there won't be [an Iranian] nuclear program," he said. "And that's the incorrect part of the sentence."
Diskin cited "experts" who predicted a military strike would actually speed up Iran's nuclear program, with Tehran using an attack to legitimize its efforts.
Iran maintains its nuclear program is for peaceful civilian uses.
Dagan told the Post in New York Sunday Diskin was expressing his "internal truth" and called him a good friend and a serious person.
Neither Barak nor Netanyahu commented on Diskin's remarks but sources close to the prime minister called the comments "irresponsible."
The criticisms came several days after the Israeli military chief described the Iranian government as "rational" and said he did not believe it would build a nuclear bomb.
"I believe he would be making an enormous mistake, and I don't think he will want to go the extra mile," Lt. Gen. Benny Gantz, the Israeli military chief of staff, told Haaretz in remarks published Wednesday, referring to Iranian Supreme Leader Ayatollah Ali Khamenei
"I think the Iranian leadership is composed of very rational people," Gantz said. "But I agree that such a capability, in the hands of Islamic fundamentalists who at particular moments could make different calculations, is dangerous."