The Department of Health makes no specific recommendations for visitors to New Zealand. However, you may like to check with your doctor before departure and read the Department of Health booklet Health Advice for Travellers, available from post offices and supplied with your travel documents. There are reciprocal health agreements between New Zealand and the UK, so UK citizens are entitled to free treatment as a hospital in-patient, but must pay some charges for services provided as outpatients and by private doctors. Visitors bringing in medications should make sure that they also carry a doctor’s certificate in order to avoid problems with customs. 
Worldwide Motorhoming Holidays offer fully comprehensive medical and personal holiday insurance for peace of mind while you’re away. 
In wetter areas, such as Fjiordland, sandflies can be pests, but are effectively controlled by use of insect repellent.
This is a water-borne parasite that causes diarrhoea. To avoid contracting it, it is best not to drink water from lakes, ponds or rivers without first boiling, chemically treating or filtering it.
New Zealand's clear, unpolluted atmosphere and relatively low latitudes produce sunlight a great deal stronger than much of Europe, so be prepared to wear hats and high factor sun block when out in the sun for more than a few minutes.
New Zealand’s cities and towns have excellent water supplies and in all cases tap water is fresh and safe to drink. Water from rivers and lakes should be boiled, chemically treated or filtered before drinking, to avoid stomach upsets.
New Zealand has a reputation for being one of the safest countries in the world, particularly in the countryside, but it is still good practise to be vigilant about your property, both in terms of your motorhome and personal belongings. Take sensible precautions to protect yourself from petty crime. Don’t leave your handbag or luggage unattended. Leave copies of important documents with family and friends in the UK. Carry a photocopy of your passport for ID.