Israeli Prime Minister Binyamin Netanyahu  has come under a scathing attack from a former head of Israel's internal security service over his handling of Iran's alleged nuclear programme.

Yuval Diskin, the country's former head of the Shin Bet domestic intelligence service, said in a voice clip played on Israel Radio on Saturday that the country's leaders were "messianic" and unfit to tackle the Iranian nuclear programme.

"I have no faith in the prime minister, nor in the defence minister," said Diskin in the radio clip. "I really don't have faith in a leadership that makes decisions out of messianic feelings."

Diskin also told the radio listenership that while he did not think Netanyahu's decision was an "illegitimate decision", he was "really" afraid that "these are not the people whom I'd like to see at the wheel during an operation like that".

Other retired officials have also criticised Netanyah and his defence minister, Ehud Barak's, rhetoric of intentions to open an unprecedented front with Iran and, potentially, with its allies on Israel's borders.

Netanyahu's former Mossad foreign intelligence director, Meir Dagan, last year also ridiculed the Israeli war option.

However, Diskin's has been the most harsh criticism of Netanyahu's threat of a pre-emptive strike on Iran if diplomacy fails.

"They're creating a false impression about the Iranian issue," said Diskin. "They're appealing to the stupid public, if you'll pardon me for the phrasing, and telling them that if Israel acts, there won't be an [Iranian] nuclear bomb."

'Summer of tensions'

Government officials rebuked Diskin and questioned his motives, implying that he had his eye on a political career or was settling scores after Netanyahu denied him a promotion.

Commenting on Diskin's remarks, Amos Harel of the Haaretz newspaper said the temperature was rising in anticipation of the nuclear talks.

"Nothing has been determined in the Iranian story, and the spring is about to boil over into another summer of tension," said Harel.

Diskin spoke days after Israel's top military commander, Lieutenant-General Benny Gantz, told the newspaper that he viewed Iran as "very rational" and unlikely to build a bomb, comments that apparently undermined the case for a strike.

Netanyahu's rhetoric about a nuclear-armed Iran have stirred concern in Israel and abroad of a possible strike against its uranium enrichment programme.

Iran says the project is entirely peaceful and has promised wide-ranging reprisals for any attack.

World powers, sharing Israeli suspicions that Iran has a covert bomb-making plan, are trying to curb it through sanctions and negotiations.

Talks to do so are to resume in Baghdad on May 23, but US President Barak Obama rated on Thursday their chance of succeeding as low.

Some experts believe that Netanyahu's stance is a "bluff" to keep up pressure on the Iranians.