When Jennifer Green prepares to visit the market in Tehran, she wraps a scarf around her head, puts on a clean pair of white gloves and places an N95 air mask securely over her nose and mouth.

Key points: Iran is third in the world, behind China and Italy, for the number of coronavirus cases

Iran is third in the world, behind China and Italy, for the number of coronavirus cases Many Iranians in self-isolation believe the Government is under-reporting the death toll in the country

Many Iranians in self-isolation believe the Government is under-reporting the death toll in the country The World Health Organisation says that while medical supplies are rapidly depleting worldwide, Iran has been hit particularly hard

She has been using her bathtub as a temporary decontamination zone for whatever groceries and household items her husband brings home, spraying packages with a mixture of iodine and salt-water, which the family also gargle with as a defence against the coronavirus.

Her husband wears assigned "outside clothes" to keep his indoor attire free from contamination in a routine that's quickly become the norm for their household.

According to government figures, almost 1,000 people have died and more than 16,000 have been infected by COVID-19 in Iran, making it the third-worst affected country behind China and Italy.

And some believe the numbers are underreported and could be much higher.

Ms Green's bathtub is full of groceries that will be sprayed and sanitised before use. ( Supplied: Jennifer Green )

Among the dead are dozens of officials, including members of Parliament and a senior adviser to the Supreme Leader.

In response to the outbreak, Iran has shut schools and universities, suspended major cultural and sporting events, cancelled Friday prayers in many regions and cut back on work hours.

"Strict preventive measures—including screening of air travellers at departure gates— are being implemented," tweeted Iran's Foreign Minister Javad Zarif.

But Ms Green said her biggest concern was not for her own family — none of whom fall into the "high-risk" category — but for the elderly, the sick and families who may not survive under the financial strain of self-isolation.

"I am also concerned about the overwhelming amount of patients in the hospitals and the impact on the doctors and nurses who are on the frontlines," she told the ABC.

"They cannot rest, and they are overstrained. How many medical staff will die and who will replace them?"

A medical system already crippled by sanctions

A firefighter disinfects a shrine in Tehran to prevent the spread of the coronavirus. ( AP: Ebrahim Noroozi )

In May 2018, the US withdrew from a multi-nation deal that had ended Iranian sanctions in exchange for limits on Iran's nuclear program.

A series of renewed US sanctions against Iran have ensued, devasting Iran's economy and ultimately inhibiting the Islamic republic's ability to deal with the current crisis.

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Ms Green said the sanctions made accessing crucial supplies difficult.

"People need access to supplies because what happens if you don't have enough? You must get selective — that's horrifying," Ms Green said.

The Iranian Health Ministry and the Iranian Embassy in Canberra did not respond to requests for comment, but Iran's Foreign Minister has been posting updates on the situation via Twitter.

Mr Zarif wrote that despite having excellent medical facilities and health workers, "we are stymied in our efforts to identify and treat our patients, in combatting the spread of the virus, and, ultimately, in defeating it".

Last week, Mr Zarif wrote to UN secretary-general Antonio Guterres asking the UN and member states to support Iran's demands for relief from "economic terrorism" and the lifting of all US sanctions to allow the country to effectively deal with the pandemic.

"Illegal US secondary sanctions make it virtually impossible for Iranians … to import medicine and medical equipment," he wrote.

Speaking to reporters in Geneva earlier this month, Michael Ryan — head of the World Health Organisation's emergencies program — said while medical supplies were rapidly depleting worldwide, Iran was particularly hard hit.

"Clearly the situation in Iran is still very serious," he said adding that there was a shortage of ventilators, oxygen and protective gear.

"Those supplies are very short, and we're struggling to find other supplies externally."

This shortage of supplies has limited Iran's ability to carry out widespread testing for the virus, and many fear the number of cases and deaths from COVID-19 could be much higher than the official numbers.

'People are dying everywhere'

Among the dead are dozens of officials, including members of Parliament and a senior adviser to the Supreme Leader. ( AP: Mahmood Hosseini )

Thirty-eight-year-old Fariba — who has been in self-isolation for weeks, afraid to go out in her home city of Esfahan — said many people believed the real death toll in Iran could be close to 3,000.

"According to nurses and doctors who work in hospitals, they say it's awful," she told the ABC.

"People are dying everywhere."

Fariba, who asked to be referred to by her first name only, shared photos with the ABC of her local gym which has been turned into a makeshift hospital to keep up with demand.

"We Iranians need help from other countries, SOS," she said.

"We are really afraid to be in crowded places. So many people in Esfahan have coronavirus — we feel safer at home."

Fariba shared a photo with the ABC of her gym transformed into a makeshift hospital. ( Supplied: Fariba )

Access to the outside world for Fariba and her family has been limited. Paranoid about infection, she washes everything her husband buys immediately after it enters the house.

While she waits in the safety of the family home, her husband goes out and buys basic household needs and groceries for Fariba to cook.

But she said they were in desperate need of more sanitary products.

Fariba said criticism over the Government's response to the virus was mounting, and many believed the Iranian Government was lying about the death toll.

While some activists claim the number of deaths and infections are being deliberately under-reported, it is unclear if any discrepancy could be due to a lack of resources to confirm COVID-19 cases.

In the city of Qom — the epicentre of Iran's COVID-19 outbreak — satellite images provided by US space technology company Maxar appeared to show mass graves being dug as an extension of the city's largest cemetery.

Satellite images show new burial plots at a cemetery in Qom, Iran, early in March. ( Supplied: Maxar Technologies )

Kianoush, a systems analyst from Tehran, said the new graves could be preparations for what was to come.

"According to the leaders of the modern world, the infection rate of coronavirus will be 40-70 per cent," he said.

"In Qom, the population is 1.2 million; if you say 50 per cent will be infected, you have 600,000 infected people. With a death rate of 3 per cent minimum, that will be around 18,000 deaths."

He said preparing a place to bury the bodies would be a smart move.

"They have to be ahead of this so that no bodies are held longer and increase the infection rate," he said.

"Is this wrong to be ready in advance? Is Australia ready for the burials about to happen?"

'We do not trust the official statistics'

Kaveh Taheri, Turkey-based Iran researcher and chairman at the Institute of Capacity Building for Human Rights, said there were no "reliable" statistics on the number of cases or deaths in Iran, claiming Iranian officials hid the first suspected cases for political reasons.

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"The situation in Iran is in high-security alert, and the security agents arrest those medical staff who leak the information or details about the issue," Mr Taheri said.

A report published on health sciences website medRxiv, titled Estimation of COVID-2019 Burden and Potential for International Dissemination of Infection from Iran, made an estimate based on the three internationally exported cases that had occurred by February 23 — within days of the government reporting the country's first few coronavirus cases.

The authors estimated 18,300 COVID-19 cases would have had to have occurred in Iran at that time "in order to observe these three internationally exported cases reported at the time of writing".

If correct, those numbers would have increased dramatically in the weeks since as the virus continued to spread.

By March 4, 97 cases had been exported from Iran to 11 countries according to the WHO.

"Based on grassroots reports received from the country, I am convinced that the estimates would be very close to reality and we do not trust the official statistics," Mr Taheri said.

"Iranians inside the country are extremely frightened, and they don't know how to get rid of the fatal virus … You cannot imagine how desperate the people are."

Mr Taheri said he was very worried for family members inside Iran, two of which had already contracted the virus.

"My mum also suspects she has coronavirus, but she was told to stay at home unless her condition gets worse because the hospitals have been left overloaded," he said.

Mr Taheri said he believed the current situation would further anger citizens who had taken to the streets in recent times to protest inflation, unemployment and widening inequality in the wake of increasing US sanctions.

Iranian authorities have denied under-reporting coronavirus cases. ( AP: Vahid Salemi )

"Iran's oil export has reached its lowest level in the past four decades, and the regime does not have enough resources for small businesses inside Iran to move through the crisis," Mr Taheri said.

"Iranians will take to the streets again after the eradication of coronavirus in the country, even wider and wider than what we saw during the 2019 Iran protests."

The most recent wave of protests followed Iran's shooting down of a passenger plane that was misidentified as a US cruise missile, which left 176 people dead.

Iran initially denied responsibility, until US and Canadian intelligence agencies uncovered evidence.

Protesters condemned authorities for not initially telling the truth.

'I'm not afraid'

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While life amid coronavirus has caused fear, panic buying and isolation across the globe, Ms Green, who is a US citizen temporarily living in Iran, says it is important to focus on the positive ways Iranians are helping each other.

"This is a hard place to survive right now, yet they are still taking time to help others," she said.

"People with much less than others are still taking time to be human and decent, even though many are going to die."

As a teen, Ms Green lived in China during the SARS outbreak and still remembers it well.

She said getting through that outbreak perhaps prepared her for what was to come in Iran.

"I'm not afraid because there's no-one in our home who fits the criteria for the more at risk," she said.

Ms Green said she had witnessed many acts of kindness including random people giving out hand-made face masks and gloves, and heard stories of volunteers sanitising ATM machines, as well as doctors and nurses dancing to liven up spirits.

"There is an underlying belief here that if you want to be safe from the coronavirus, you must protect those near you too. How can you be safe if your neighbours get infected?"