Iran orchestrated at least two alleged antisemitic firebombings on Australian soil last year by hiring criminals to do their bidding, in what authorities described as an"unprecedented attack".

Prime Minister Anthony Albanese said spy agency ASIO has determined Iran was behind the fires that gutted the Lewis' Continental Kitchen in Sydney on October 20 and the Adass Israel Synagogue in Melbourne on December 6.

Iran's Ambassador to Australia, Ahmad Sadeghi, as well as three other Iranian officials, have been expelled, the Australian embassy in Tehran has been closed, and Iran's Revolutionary Guard Corps (IRGC) will be declared a terrorist organisation.

Today was the first time Canberra has declared a foreign ambassador persona non grata since the end of World War II.

"These were extraordinary and dangerous acts of aggression orchestrated by a foreign nation on Australian soil," Albanese said.

"They were attempts to undermine social cohesion and sow discord in our community."

ASIO Director-General Mike Burgess said his investigation uncovered links between the two incidents and the IRGC.

"The IRGC used a complex web of proxies to hide its involvement," he said.

The IRGC was found to have used people in the criminal world to direct these alleged attacks, some of whom were paid to do so.

"It's a series of chains," Burgess said.

"There's an organised crime element offshore in this, but that's not to suggest organised crime are doing it.

"They're just using cut-outs."

ASIO is currently investigating Iran's potential involvement in a number of other attacks.

Home Affairs Minister Tony Burke said Iran's actions were an"unprecedented attack" on Australia.

"It's aimed at creating fear, stoking internal divisions, and eroding social cohesion. It's true that no one was injured in these attacks, it's not true that no one was harmed," he said.

Australia expels ambassador, pulls out of Iran

Australia has notified Iran's Ambassador to Australia, Ahmad Sadeghi, and three other Iranian officials that they have been expelled and have seven days to leave Australia.

No Iranian diplomats have been accused of being directly involved in the two attacks.

The last ambassador to be expelled was Japan's Tatsuo Kawai in 1942, a year after Australia declared war on Japan.

Australia has suspended operations at its embassy in Tehran, with all staff pulled from the country. All diplomats are safe in a third country.

Albanese announced his government will introduce legislation to list the Revolutionary Guard as a terrorist organisation.

"Any attack on our social cohesion is an attack on Australia," he said.

"We are proud of the country that we've built. A country where people can live overwhelmingly side by side of different faith, of different background, in harmony.

"We cherish it. We protect it. We defend it. And that's what we're doing here today."

The opposition supported the federal government's measures in parliament.

"These acts of egregious foreign interference are brazen attempts to cleave apart our social cohesion, to turn neighbour against neighbour and Australian against Australian," Opposition Leader Sussan Ley said.

"While we sit opposite the government in this chamber, we're entirely united on the measures announced today to expel the Iranian ambassador and list the Iranian Revolutionary Guard Corps as a terrorist organisation."

Australians told to leave Iran

Foreign Minister Penny Wong acknowledged that it was a distressing time for Australia.

"I know many Australians have family connections in Iran, but I urge any Australian who may be considering travelling to Iran, please do not do so," she said.

"If you're an Australian in Iran, leave now if it is safe to do so."

The Department of Foreign Affairs has updated its travel advice for Iran, urging Australians not to travel and to leave the country.

"Foreigners in Iran, including Australians and dual Australian-Iranian nationals, are at a high risk of arbitrary detention or arrest," a statement from Smarttraveller said.

"Our ability to provide consular assistance in Iran is extremely limited."

Australians in need of consular assistance should call the Australian Government 24-hour Consular Emergency Centre on 1300 555 135 in Australia or +61 2 6261 3305 outside Australia.

Australian Jewish community feeling 'great anxiety'

NSW Jewish Board of Deputies president David Ossip said today's announcement was"chilling and deeply concerning".

"It is difficult to overstate the significance of this unprecedented news," he said.

"These incidents were nothing less than an attack on Australia by a foreign state, primarily targeting the Jewish community and designed to unravel our social cohesion by legitimising and normalising attacks on the Jewish community."

Ossip said the community had been gaslit about the extent of the threat against them.

"Those who sought to downplay the threat against the Jewish community or dismiss the campaign of terror targeting our community as a criminal con-job or hoax owe the Jewish community an apology," he said.

Executive Council of Australian Jewry president Daniel Aghion said the community may find some solace in the breakthrough.

"Yet there will be great anxiety that we have been targeted in such a callous and calculated way, by a ruthless and violent foreign force, because of who we are," he said. 

The incidents Iran orchestrated in Australia

Lewis' Continental Kitchen in Sydney was destroyed in an alleged firebombing on October 20.

Former Nomads bikie boss Sayed Moosawi, 32, was one of more than a dozen people charged over two alleged antisemitic attacks, including the one on Lewis' Continental Kitchen.

Police alleged he set the deli alight after the two criminals he hired to do his bidding wrongly targeted a nearby brewery.

Moosawi has denied the allegations against him and remains before the court.

NSW Premier Chris Minns said state police will work closely with federal agencies to ensure the safety of places of worship, businesses, and community members.

"Our message is clear: hate has no place in NSW, and those who seek to divide us will not succeed," he said off the back of today's announcement. 

The Adass Israel Synagogue in Melbourne was also gutted after a firebombing on December 6, rocking the local Jewish community.

Two men, 20 and 21, were charged with deliberately setting fire to the building.

A third man, 20, was charged with stealing a car used to drive to the synagogue.