Members of the public are being advised to exercise caution when in contact with shallow water following two reports at the south end of Lake Taupo of allergic rash.
"Although not confirmed, it is possible these may be cases of cercarial dermatitis, also known as 'swimmer's itch' or 'duck itch'.
"This is caused by exposure to tiny larvae or cercariae in the water, most commonly found in shallow and relatively warm areas," Toi Te Ora - Public Health Service medical officer of health Dr Jim Miller said.
The larvae can cause an allergic irritation of the skin which was generally minor and self-limiting, however, if the rash was extensive or did not improve for more than a few days, people should seek medical advice, he said.
"Any irritation should run its course, but can usually be easily treated with soothing antihistamine or steroid creams. Always see your doctor if symptoms persist."
