Gardeners are being encouraged to take simple precautions when handling potting mix, mulch, and compost to avoid contracting Legionnaires' disease.

Legionella longbeachae bacteria are often found in soil products and can cause the lung infection Legionnaires' disease if someone inhales dust from contaminated gardening products.

NSW Health Executive Director, Health Protection, Dr Jeremy McAnulty, said gardeners should read and follow the manufacturer's warnings on bagged potting mix.

"Before opening the bag, put on a mask and gloves so you don't breathe in the dust or get it on your hands. Wetting the potting mix, mulch or compost can reduce the dust blowing up into the air," Dr McAnulty said.

"Even if you've been wearing gloves, make sure to wash your hands thoroughly with soap before eating or drinking as the bacteria could still be there."

There have been 54 cases of Legionnaires' disease so far this year from the type of bacteria that can be found in potting mix and soils in NSW, and 132 cases were reported last year.

Symptoms of Legionnaires' disease include fever, chills, a cough, shortness of breath, aching muscles, headache, tiredness, loss of appetite and diarrhoea. It can develop up to 10 days after exposure to the bacteria.

''Most people who breathe in the bacteria don't become ill, but the risk of infection increases if you're older, a smoker, or have a weakened immune system," Dr McAnulty said.

Legionnaires' disease can usually be cured by treatment with antibiotics, however, it can require hospital care and be fatal in some people.

It is not spread from person to person.

This type of bacteria found in potting mix is a different strain of the same bacteria which is found in contaminated air conditioning cooling systems on large buildings. The disease caused by both strains is known as Legionnaires' disease.

If you have ongoing or worsening symptoms, you should see your doctor or visit your local emergency department.

For more information on Legionnaires' disease, please refer to Legionnaires' disease fact sheet.