Grass pollen days are expected in Victoria this spring
It follows Victoria's wettest winter in a decade and the warmest on record in Melbourne.
The Department of Health will begin issuing daily thunderstorm asthma forecasts next week.
Much of Victoria could experience a more active hayfever season after this year's warm, wet winter.
Seasonal hayfever affects people who are allergic to tree and grass pollen, which are released into the air during spring.
Tree pollen season is already underway in Melbourne, with cypress trees responsible for a number of ratings being issued by air-monitoring service Melbourne Pollen already this spring.
Grass pollen season starts on October 1.
Last year, there were five grass pollen days and 15 high grass pollen days in Melbourne.
With Victoria recording its wettest winter in a decade and above-average temperatures, Melbourne Pollen said the state was likely to see grass pollen days this year.
"We are seeing conditions that look more favourable to a larger year than we did last year," said Edwin Lampugnani, the CEO of AirWatch, which runs Melbourne Pollen.
"That's really driven by the satellite data that we're seeing, with lots of greenness in those north-western pasture lands."
Dr Lampugnani said western and central Victoria could be affected by the more active season, but there was better news for the east of the state.
"In the Gippsland region, we are seeing dry conditions and the prediction is that we are going to have lower amounts of rainfall in that area, and so for the Gippsland area we're expecting a subdued pollen season," he said.
And there is hope that the current El Niño weather pattern affecting Australia could give rise to a shorter hayfever season.
"We're not going to be having those wet summers," Cenk Suphioglu, a professor of biomedical science at Deakin University, said.
"Those grass, with the recurring heat, will essentially dry them up and desiccate them so … the season is short."
Melbourne's geography and climate, including the state's wind patterns, had led to the city being dubbed the world's hayfever capital by Professor Suphioglu's pollen science centre, AirWatch.
Professor Suphioglu said rye grass was grown extensively for livestock feed on farmlands to the north-west of Melbourne.
He said the grass produced large amounts of pollen, which was carried on northerly winds to the city.
He said residents of Melbourne's west were the most affected, while those living to the east of Port Phillip reaped the rewards of a naturally occurring pollen filter.
"We have this large body of water in our bay," Professor Suphioglu said.
"As the pollen is travelling over the water, if they then suddenly settle on top of the water, it's going to be a water filtration effect.
"If you can relocate to the [Mornington] Peninsula, or the further you go on the other side of the water, … the better for you."
Hayfever symptoms include sneezing, coughing and an itchy nose, eyes and throat.
Medical experts have previously told the ABC antihistamine tablets can help those suffering mild symptoms of hayfever, but people with cases may need a nasal spray, including a corticosteroid or anti-inflammatory spray.
Eye drops from a pharmacy can help soothe watery, itchy eyes.
Those with severe symptoms can speak to their doctor about whether they should be referred to an allergy specialist for desensitisation immunotherapy.
Under certain conditions, hayfever sufferers can experience respiratory distress.
"Thunderstorm asthma is a particular condition that occurs when certain types of storms, combined with very high or extreme levels of grass pollen, occur simultaneously," Dr Lampugnani said.
"Under those conditions, grass pollen can rupture, turn into very small particles, and those small particles can go down into your lungs and cause asthma-like symptoms."
November 21 will be the 10th anniversary of Melbourne's thunderstorm asthma event that killed nine people and forced thousands to seek urgent medical help.
At the end of a hot day, a severe thunderstorm swept across Melbourne and Geelong.
"The storm was followed by an epidemic thunderstorm asthma event, the likes of which, in terms of size, severity and acuity, had never before been seen, nor even imagined, let alone planned for," then-Victorian chief health officer Charles Guest said in a 2017 report.
"It resulted in thousands of people developing breathing difficulties in a short period of time, creating unparalleled demand across the health service system.
"For many of those affected, this was their first asthma attack."
The health department has since declared it the world's largest epidemic thunderstorm asthma event.
Professor Guest's report said there was a 672 per cent increase in respiratory-related presentations to Victorian emergency departments over the following 30 hours, and a 992 per cent increase in asthma-related hospital admissions in Melbourne and Geelong.
He said there was a 3,000 per cent increase in asthma-related intensive care admissions.
Thunderstorm asthma forecasts are issued by the Department of Health and are available through the Vic Emergency app.
The daily forecasts will begin next week, coinciding with the grass pollen season.
"It's really important that you start preparing now," Dr Lampugnani said.
"Make sure you have an asthma action plan in place and that you've spoken to your GP about treating your condition.
"You can treat it, of course, once you start experiencing symptoms, but by that time, some of the treatments are not as effective."