Lives could have been saved during a deadly thunderstorm asthma event in Melbourne if people had been given accurate ambulance arrival times, victim's families say.
Ten people died, including seven men and three women, during or soon after the storm hit Melbourne on November 21, 2016.
A combination of high pollen levels, strong winds, hot temperatures, air moisture and a cold front triggered severe asthma attacks and an unprecedented surge in demand for ambulances.
Family members of electrical fitter Priyantha Peiris said better estimated ambulance arrival times could have saved lives.
"It would have saved a lot of lives," one family member told AAP.
"When you ring for an ambulance that you are told exactly as to what the situation is, so you know that the person who rings up can take them to the nearest doctor or hospital," she said.
The 57-year-old man died at the Northern Hospital in Epping on November 29, eight days after the storm hit the city.
Mr Peiris' wife could have taken him to the nearest doctor, just two minutes away, if she had been given accurate information, family said.
"Just be honest with the answers," a loved one said about arrival times.
The coroner said she accepted genuine changes had been made to ambulance scripts for times of high demand, but would like more improvement.
"It is not apparent that a caller hearing the new scripts is in any better position to make an informed choice about whether to wait for an ambulance or to engage in self-help," coroner Paresa Spanos said.
"What such a caller needs is information specific to their situation, effectively an estimated time of arrival of the ambulance," Ms Spanos said.
The new scripts changed from "the ambulance is on its way" to "help is being arranged" which is more accurate during times of high demand, findings show.
Work was being done to put in place estimated arrival times, Ambulance Victoria emergency operations director Mick Stephenson said.
"The possibility of providing people with an estimated time frame for an ambulance to arrive is being explored at the moment within Ambulance Victoria," Mr Stephenson said.
"It is highly likely we will roll out a pilot of that some stage in the not too distant future."
He said it was "very difficult" to give people an accurate time frame because ambulances had to be diverted to sicker patients if needed.
While the coroner made no official recommendations because "so many had been made, and few stones left unturned" there were other areas that needed ongoing work and improvement.
She called for more research into the meteorological, biological and aerobiological factors that caused thunderstorm asthma and that public awareness campaigns should continue.
Ms Spanos also said there was further scope for more medical, allied health and general community education to encourage hayfever sufferers to undergo allergy testing for their own benefit.