The former director of Israel's intelligence agency Mossad, Efraim Halevy, says former Hezbollah leader Hassan Nasrallah "deserved" to be assassinated.

Nasrallah was killed in the final days of September, when Israel launched a series of massive air strikes into southern Beirut.

The strikes were the catalyst for an escalation in the conflict in recent days and saw Iran launch what Israel says were 180 ballistic missiles into its territory.

Iran's Revolutionary Guards say they used hypersonic Fattah missiles for the first time, and that 90 per cent of their missiles successfully hit their targets in Israel.

While Mr Halevy was adamant Nasrallah needed to be killed, the former Mossad chief said he was surprised at the scale of Iran's attack on Israel.

"I believe that we were not going to expect this degree of response," he said.

"The problem that we were facing was not only their attempt to revenge themselves of an alleged assassination we carried out in the capital a few months ago for which Israel did not assume responsibility, but for what happened in Lebanon when we killed Nasrallah, who was their man on the spot.

"The entire movement in Lebanon of the Hezbollah are an offshoot of the Iranian intelligence complex.

"From their point of view they believed they had to respond and take their vengeance for what we had dealt Hezbollah.

"[That came] after their action against us for months where tens of thousands of Israelis had to leave their homes in the north ... because they were in the sight of the Hezbollah artillery."

Escalating tensions

Israel is already involved in a ground invasion of Gaza, as retaliation for last year's October 7 attacks and has in recent days launched a limited operation into Lebanon.

The missiles launched from Iran into Israel have stoked fears of a winder conflict in the Middle East.

Iranian President Masoud Pezeshkian said Iran's attack on Israel was "based on legitimate rights" and "with the aim of peace and security".

"This action was in defence of the interests and citizens of Iran," he wrote on a social media post on X.

The president's comments were reported by several Iranian outlets.

Call for Netanyahu to show restraint

Mr Halevy, who was appointed to his previous post by Mr Netanyahu, said the strongman leader had to think carefully about his next steps.

"From our point of view, we have to take into account the many people who were murdered in Lebanon, and also in to take into account the people who were killed in attacks of the Hezbollah inside Israeli territory," Mr Halevy told 7.30.

"We have to decide whether we are interested in a a large scale response.

Mr Halevy said a war with Iran would present large challenges but he told 7.30 his expectation was that Mr Netanyahu would not choose that option.

"I won't say we won't be able to win, but Iran is a much larger country than Israel with a much larger population," he said.

"I think it would be wise for Israel not to go instantaneously to the top of the ladder but maybe do something else and give the Iranians one more option of not retaliating back."

Asked if he thought peace was something that Mr Netanyahu could bring to Israel and the Middle East, the former Mossad director seemed unconvinced.

"I have been critical of the way he has handled the affairs of Israel in recent years," Mr Halevy said.