Hundreds raise flags and 'pro-democracy' slogans at Iranian embassy in Canberra

The crowd had about 300 people in it, an ACT Policing spokeswoman confirmed.

At least 20 police officers were seen lined outside the foreign embassy as demonstrators with Iranian, Israeli, American, and Australian flags gathered at the location and demanded a regime change in Iran.

A sign outside the building which previously said "The Embassy of the Islamic Republic of Iran" had been defaced and now said "Javid Shah" in black spray paint.

"Javid Shah, Javid Shah Javid Shah," the crowd was heard chanting loudly in a video of the demonstration in O'Malley.

People had travelled from Sydney and Melbourne to join the crowd on Thursday, a protester who did not want to be named told The Canberra Times.

The man, who lives in Canberra, said Javid Shah translated to "long live the King".

"We support the people of Iran ... countries, including US and Australia, they support the Iranian movement," he said.

He said more than 1000 people were part of the Iranian diaspora in the ACT, but many did not attend the demonstration fearing backlash against family and friends who live in Iran.

"Most of us have relatives in Iran, but we don't have any way to contact each other because the internet has been cut ... for four or five days," the man said.

Several demonstrations have been reported in Canberra this week, including at the US embassy, in tandem with those organised in other Australian cities since mass protests erupted in Iran more than two weeks ago.

About the same time, multiple reports say protesters pulled down the existing flag at the Iranian embassy and replaced it with an older "pre-revolution Iranian flag".

The embassy quickly replaced the flag on the same day, protesters who supported the restoration of the Shah, Reza Pahlavi, as a constitutional monarch in Iran, said.

According to Reuters, Iranian officials on Thursday said more than 2000 people have died while a rights group put the toll at more than 2600.

In Iran, protesters face bullets, jail and execution, while demonstrators in Australia are calling for democracy to prevail in the West Asian country.

US President Donald Trump is considering his options after threatening military action if Iran continues killing protesters.

The country's airspace has been closed, except for flights to and from the capital Tehran, with other services diverted around the country.

Foreign Minister Penny Wong said Australia continued to urge people not to travel to Iran, and warned the security situation could deteriorate rapidly.

"We would additionally advise all those in the region to avoid demonstrations and protests," she told reporters on Thursday.

James Younessi, a Sydney doctor who travelled to Canberra to speak at the demonstration, said he would happily move back to his home country if the regime was overthrown.

But he was hesitant about more American intervention in the Middle East.

"I don't want Iran to be indentured to any foreign nation the moment anybody interferes," he told AAP.

"But if it means saving one life for it, we want a measured response that we can have this bloodshed ended.

"If we can stop the bloodshed, if Mr Trump is good to his word, come save us from being killed, then leave us to govern ourselves," Dr Younessi said.

Another protester, Omid Fakhri, who had not heard from his family in Iran because of the internet blackout, was more positive about US military action.

"We don't care which military, just a military is fine, as long as they can go in and stop the massacre," he said.

- with AAP