The Murrumbidgee Local Health District's public health unit director Tracey Oakman issued the warning on Thursday morning, advising asthma sufferers that predicted thunderstorms are likely to exacerbate already difficult circumstances.

"Current high pollen counts and the predicted thunderstorms can increase the risk of asthma," she said.

"People who are known to suffer from asthma should carry their asthma puffer with them at all times and try to stay indoors with the windows and doors closed during the storm period."

Ms Oakman said people who experience breathing difficulties are advised to call triple-zero or go to the nearest emergency department.

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