Over 96 cases of E.coli have been reported in the last ten days in Ireland, a threefold increase on the same period last year.
As a result, the HSE is warning people to take extra care when handling and preparing food.
The HSE says people need to wash their hands and also wash all fresh fruit and veg.
So far, no specific reason has been discovered for the increased rate of infection.
Commenting on the figures, Dr Kevin Kelleher, the HSE's Assistant National Director, Public Health, said, “While investigations haven’t identified a specific reason for the increase in cases we would like to remind people to be careful about food safety during this heatwave to protect themselves against food poisoning.
“This hot weather provides the right conditions for bacteria such as VTEC to grow and multiply on foods which can lead to high numbers of cases of food poisoning in adults and children.
“Not washing hands after handling raw meat, not washing fruits and vegetables and undercooking minced meats such as beef burgers are common ways of getting food poisoning at this time of year.”