A eighth person is dead following Melbourne's so-called thunderstorm asthma event, while one person clings to life in intensive care, the Victorian Department of Health and Human Services said.
The death toll rose from six to eight on Tuesday, with one person still in a critical condition, authorities say.
Last week's freak weather event caused an outbreak of severe breathing difficulties across the city last week 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 were at least 8500 people treated due to the thunderstorm, with many experiencing breathing problems.
Among the eight victims are Apollo Papadopoulos, 35, law student Hope Carnevali, 20, and high-school student Omar Moujalled, 18.
The family of Carnevali has said she died in her family's arms while waiting for an ambulance to arrive.
"There have now been eight deaths that may have occurred as a result of conditions relating to the thunderstorm asthma events last week," the department of Health and Human Services said in a statement.
"One patient continues to receive specialist ICU care in a Melbourne hospital and remains in a critical condition.
"This was a tragic and unforeseen event and hospitals are continuing to treat 7 people for a variety of respiratory and other related conditions."
Last week health minister Jill Hennessy announced a state-wide review of the emergency response to the thunderstorm asthma event.