Keen gardeners in Canterbury are being reminded to take precautions to guard against Legionnaires' disease.
It comes after 23 cases of the disease have already been confirmed in the region this year.
Canterbury Medical Officer of Health Dr Ramon Pink said the disease, which is a form of pneumonia and can be fatal, thrives in bags of potting mix and compost.
"It's caused by the Legionella bacteria that live in moist organic material and people can catch the disease by inhaling airborne droplets or particles containing the bacteria.
"Gardeners are at particularly high risk of catching Legionnaires' disease as the bacteria thrive in bags of potting mix and compost," Dr Pink said.
He said there's usually a spike in cases over Labour Weekend because people get out into the garden.
When using compost people should work in a well ventilated area, wash their hands often and wear a face mask.
"To reduce dust you can spray water into the compost bag before using it.
"Legionnaires is a very serious illness and following these simple steps can be lifesaving.
"The illness may be mild but it can sometimes be fatal, it's more common in older people but sometimes even healthy young people have died from legionella pneumonia," Dr Pink said.
Symptoms include a dry cough, high fever, chills, shortness of breath, muscle aches, headaches and diarrhoea.
RNZ
