Holidaymakers in Havelock in Marlborough may have been exposed to mumps after a case was identified in the region.
People who stayed at the Blue Moon Lodge in Havelock around Christmas, or the Inlet Backpackers, Collingwood on December 27 may have been exposed to mumps.
The person with mumps has been isolated, and travellers are being told they do not need to change or cancel holiday plans, but remain alert to symptoms.
Dr Simon Baker, locum Medical Officer of Health, says that early symptoms of mumps include fever, headache, muscle aches, tiredness and loss of appetite.
Later, the salivary glands on one or both sides of the face, cheeks or jaw may become swollen and sore.
"Should you develop any of these symptoms in the next two to four weeks please isolate yourself, and contact a doctor, who will probably call you in to have a swab taken, and give you further advice," he says.
"Immunisation is the best way to protect yourself from mumps, and we recommend you check your child health book or contact your doctor to make sure you have received two doses of the MMR vaccine, and are therefore fully immunised."