Victoria's deadly asthma thunderstorm event was the worst recorded in the world, with the health minister comparing it to 150 bombs going off at once.
Victoria's deadly thunderstorm asthma attack was the worst recorded in the world.
The unprecedented event has health experts considering asking people to drive critically ill patients to hospital instead of waiting for an ambulance if it happens again.
Eight people are dead and another is in a critical condition nine days on the from the deadly storm, which resulted in 8500 patients admitted to hospital in one night and 30 put in intensive care.
"It was genuinely like having 150 bombs going off at once right across metropolitan Melbourne and places in some of the outer regions," Health Minister Jill Hennessy told reporters again on Wednesday after making the same comparison last week.
"We've just never encountered anything of the scale or the scope."
Respiratory physician Michael Sutherland, who works at the Epworth and Austin hospitals, says the asthma thunderstorm was the most severe recorded anywhere in the world.
The previous worst episode was in London in 1994 with 640 people attending emergency departments and five or six intensive care admissions, Dr Sutherland told AAP on Wednesday.
Ambulance Victoria chief executive Tony Walker said lives were lost while people waited for paramedics to arrive.
"We routinely don't recommend (to) people that they take critically ill people to hospital themselves (but) this is a different type of emergency," Mr Walker told 3AW on Wednesday.
"As part of our review we're looking at ... giving the community real-time information to enable them to make an informed decision about what they do."
Mr Walker said if Ambulance Victoria couldn't guarantee they'd be there, people should have the information required to make the decision to drive a loved one to hospital.
Every available ambulance in Melbourne was sent out on calls during the storm and paramedics saved "countless lives", but Mr Walker said the families of the eight people who died deserve to know changes would be made.
Ms Hennessy said experts and health authorities from around the world had besieged her office with offers of help and requests for information in case it happens again overseas.
Chief health officer Charles Guest told asthma sufferers to keep their medication close at hand with storms predicted for Gippsland and the state's northeast late on Wednesday.
"Thunderstorms, combined with pollen in the air, can cause an increase in asthma symptoms, hay fever and breathing difficulties," Professor Guest said in a statement.
The Department of Health and Human Services says Wednesday's storms are not expected to be another asthma thunderstorm, but it is an important chance for people prone to asthma or hayfever to make sure they are prepared.
Prof Guest also told people to stay inside when air quality is poor.
The Inspector General for Emergency Management will investigate the response to the storm, with an interim report due in January.