A sixth person has fallen victim to Melbourne's so-called thunderstorm asthma event, while five people still cling to life in intensive care.
"There have now been six deaths that may have occurred as a result of conditions relating to the thunderstorm asthma events on Monday," the Nine Network quotes a health department spokesman as saying on Sunday.
The latest death brings total fatalities linked to the storm to six. Two people have so far passed away on Sunday from health problems caused by the storm.
The state's Health Minister, Jill Hennessy, said it was tragic to see the death toll rise almost a week after the storm swept across the Victorian capital.
"We still have five people in intensive care units and three of those people are very critically unwell. Many of our patients have been disharged into wards but the vast majority of patients have been discharged," Hennessy said.
The freak weather event caused an outbreak of severe breathing difficulties across the city on Monday and sparked 1900 calls to emergency services which Ambulance Victoria said was six-times the normal rate, while an additional 60 ambulances were put on to keep up with demand.
There have been at least 8500 people treated due to the thunderstorm, many experiencing breathing problems.
Among the five victims are Apollo Papadopoulos, 35, law student Hope Carnevali, 20, and high-school student Omar Moujalled, 18. Alarmingly, the family of Carnevali has said she died in her family's arms while waiting for an ambulance to arrive.
The fifth victim is believed to be a woman and died at Northern Hospital in Epping on Friday night, according to Sky News.
The Inspector General for Emergency Management in Victoria will reportedly examine the cause of the deaths, with findings forming part of a sweeping review that will look at how emergency services responded to the crisis.
In addition to the five people still in a critical condition there are another 20 people being treated for respiratory and related conditions, according to Sky News.
A freak weather occurrence, thunderstorm asthma is triggered by large storms that can cause significant breathing problems even for totally healthy people.
The big issue on Monday was that the torrential rain combined with a high pollen count, sending millions of small particles across the city.