Israel has already breached its own red line set by Prime Minister Benjamin Netanyahu by acquiring "dozens of nuclear warheads," Iranian Defence Minister Ahmad Vahidi said on Saturday.

"If having the atomic bomb is passing the red line, the Zionist regime, that possesses dozens of nuclear warheads and weapons of mass destruction, has passed the red line years ago, and it has to be stopped," he said, according to the ISNA news agency.

Vahidi was responding to a speech by Netanyahu to the UN General Assembly this week in which -- using a cartoon bomb diagramme -- the Israeli leader called for a "clear red line" to be applied to Iran's nuclear activities, which he charged are aimed at developing atomic weapons.

"Is the occupying and aggressor Zionist regime that possesses nuclear weapons more dangerous? Or an Iran that doesn't have nuclear weapons and which insists more than anybody on nuclear disarmament, and seeks only to have peaceful nuclear energy abiding by international rules," Vahidi asked.

Israel is the Middle East's sole, though undeclared, nuclear weapons state. Analysts estimate it has more than 200 nuclear warheads.

It is a member of the International Atomic Energy Agency but has never signed the nuclear Non-Proliferation Treaty.

Iran insists its nuclear programme is entirely peaceful and rejects Israel's accusations of military intent.

Israel has had serious differences with Washington over how to respond to what it regards an "existential" threat from Tehran.

US intelligence agencies estimate that Iran has taken no decision to acquire a nuclear weapon but is merely seeking a so-called breakout capability to develop one in the future if it so decides.

It says there is more time for diplomacy and sanctions to work out.