The Bureau of Meteorology has forecast possible severe thunderstorms for the ACT on Saturday with up to 60 millimetres of rain expected.

This combined with elevated pollen levels could result in thunderstorm asthma, ACT Health says.

Thunderstorm asthma is triggered by high pollen levels and thunderstorms which can cause people to develop asthma symptoms over a short period of time.

But ACT Health has said that not all thunderstorms produce an asthma event and that thunderstorm asthma is a rare event. People who suffer from hay fever or asthma are encouraged to be vigilant over the weekend.

"Where possible avoid being outside during a thunderstorm - especially in the wind gusts that come before the storm," an ACT Health statement said.

"Go inside and close your doors and windows. If you have your air conditioning on, turn it onto recirculate."