VICTORIA is approaching the peak of the grass pollen season when hay fever and asthma cases are at their worst.

The co–ordinator of Melbourne Pollen Count, Professor Ed Newbigin, says towns in northern Victoria including Shepparton and Bendigo are having a heavy pollen season, along with the ACT and parts of NSW.

Melbourne's mass thunderstorm asthma event happened in late November 2016, with 10 fatalities and about 1400 people treated in hospital.

Those affected included people with and without a history of asthma, those with undiagnosed asthma and others with seasonal hay fever.

But cold weather and southerly winds have meant a different story for the city this year, Prof Newbigin says.

"The past couple of weeks have been wet, which has washed the pollen out of the air, and southerly winds coming across Bass Strait have not been bringing pollen into Melbourne," he told AAP. – AAP