The Murrumbidgee Local Health District has issued an alert for thunderstorm asthma for this Friday, Saturday and Sunday.

Respiratory clinical nurse consultant Robyn Paton warned that current high pollen counts and the predicted thunderstorms could increase the risk of asthma, making it a "dangerous" period for those with the condition.

"It's the sort of asthma that can occur really quickly and it comes on because of the particle size of the pollen," she said.

"We have lots of pollen because we are having a really good season with intermittent rain.

"The pollen gets whipped up into the thunderstorm ... then what happens is the protein expands and explodes which produces a very fine protein particle which gets right down into the airways."

Ms Paton said it is prevalent for people with hayfever as they tend to breathe through their mouth, instead of their nose.

She added those with asthma should carry their puffer at all times and try to stay indoors with the windows and doors closed during the storm period.

"The best control we have is for people to follow their asthma action plan," Ms Paton said.

"They need to take their preventative [medicine] and carry their reliever at all time."

Those who find they are still having trouble breathing should call an ambulance or ask someone to drive them to hospital.

"I think what has happened since COVID is people are reluctant to come to the emergency department or even to their GPs because they are concerned about the COVID presentations," Ms Paton said.

"But, if you are finding it hard to breathe, then it is important to go. That way, you can get treatment, and the asthma can be reversed."

In the event of an asthma emergency, dial Triple-Zero immediately. To receive an SMS alert when the pollen counts are high and thunderstorms are predicted, go to www.science.csu.edu.au/asthma and register.