Health authorities in Canterbury are considering asking for masks to be sold with potting mix, after another spate of legionnaires' disease cases in the region.
Three people were diagnosed with the disease in Canterbury last week, bringing the total to 10 in the region since the start of November.
Legionnaires' disease is a pneumonia caused by legionella bacteria commonly found in water and soil.
The Medical Officer of Health for Canterbury, Dr Alistair Humphrey, says warnings on bags of potting mix are not very specific.
He says if masks were attached to potting mix bags, people would at least be given the opportunity for some added protection, and it might also highlight the risks more clearly.