The wife of Australia's first coronavirus fatality says her husband died "peacefully" in a Perth hospital.

Retired travel agent James Kwan, 78, was being treated in the intensive care unit at Sir Charles Gairdner Hospital and died yesterday morning.

"My husband passed away peacefully knowing that his family loved him," his wife Theresa, 79, said in a written statement.

James Kwan is the first Australian to die from COVID-19. (Supplied)

Mrs Kwan was also diagnosed with the virus.

She is in a stable condition at the same hospital.

Both contracted the virus on board the Diamond Princess cruise ship, where they were travelling with their son and daughter-in-law.

The family has asked for privacy as they grieve.

Ambulances parked outside the Sir Charles Gairdner Hospital in Perth where a man has died from coronavirus. (AAP)

WA's chief health officer Andrew Robertson said the man was diagnosed about 10 days ago while in isolation at Howard Springs after being quarantined aboard the cruise ship and then flown out of Japan.

Mrs Kwan had the opportunity to speak to her husband before he died, he said.

"He was in his late 70s. Like many people of that age, they're more likely to have other chronic conditions and it would obviously make being able to fight off this virus more difficult," he said.

Dr Robertson said the man had earlier been listed as stable, but later deteriorated.

That was not uncommon with this disease, which often worsened in the second week when it moved from the upper respiratory tract into the lower respiratory tract, possibly causing viral pneumonia, Dr Robertson said.

He said Australia should be prepared for more cases of the coronavirus , but that most cases would be mild.

"People should be aware but not alarmed at this stage," he said, adding he was confident there had been no community spread of the disease.

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"I don't think we should be panicking at any time, this is the time we prepare for cases in the future."

Prime Minister Scott Morrison said he was "very saddened" to hear about the death of the elderly Perth man.

"We join his family and friends in mourning his passing ... We will continue to do all we can to protect Australians from coronavirus," he said in a tweet on Sunday.

Meanwhile, a fifth case of coronavirus has been confirmed in New South Wales, taking the nation's total to 27 infections.

A man aged in his 40s was diagnosed with COVID-19 after recently travelling to Iran, according to NSW Health.

He has been admitted to Westmead Hospital with mild symptoms which didn't appear until two days after he returned to Australia.

Yesterday, it was revealed a 63-year-old beautician on the Gold Coast is also in isolation after testing positive to the virus.

The woman had also recently returned from Iran.

Iran has the largest reported number of deaths from coronavirus outside of Hubei Province and the number of cases is widely believed to be under-estimated.

Federal Health Minister Greg Hunt said the Morrison government had a national COVID-19 plan with health authorities across the country meeting daily to monitor the situation.

"With the international spread of this virus, it is almost inevitable that we will see more cases of COVID-19 in Australia in coming weeks," he said in a statement on Sunday.

It comes as the government defends its decision to ban foreign visitors entering Australia from Iran to prevent the spread of the coronavirus, rather than South Korea which has a much higher level of cases.

Home Affairs Minister Peter Dutton on Sunday said that of the 106 deaths that have been reported outside of China, 43 have been in Iran.

The National Security Council has increased the warning advice level to four 'Do Not Travel' as of tomorrow, which means Australians will not be able to travel to Iran and anyone returning from the country will be required to stay in quarantine for a minimum 14 days until they are cleared.

Foreign nationals who are in Iran will be banned from entering Australia for 14 days , from the time they have left or transited through.

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The same warning is in place for China. Australians travelling to South Korea, Japan, Mongolia and northern Italy have been advised to "exercise a high degree of caution".

Globally, there are more than 86,000 people known to have been infected and more than 2900 deaths.