New Zealand sandflies are tiny biting insects found most noticeably around the South Island's West Coast, Fiordland and other damp bush or waterside areas. They are called namu in te reo Māori. Sandfly bites are irritating, but most settle without medical treatment.
Where are sandflies common in New Zealand?
Travellers often notice sandflies around Milford Sound, Fiordland, the West Coast, lakes, rivers and forest margins. The Department of Conservation warns visitors to carry insect repellent in Fiordland and other affected parks. Conditions vary with location and weather, so one campsite can feel quiet while another nearby has many insects.
South Island regions where travellers report sand flies
Sandflies can occur in many parts of New Zealand, but visitors commonly prepare for them on the South Island's wet western side. Fiordland, Milford Sound and the West Coast have abundant flowing water and damp bush habitat. They can also occur beside rivers and lakes elsewhere on the South Island.
That does not mean every stop will be covered in sand flies. Exposure changes with weather, time of day and the exact location. Queenstown and Wānaka travellers may encounter fewer at a dry, exposed town location than beside sheltered bush or water, while Rotorua visitors may be more concerned about mosquitoes in some conditions. Carrying a small repellent avoids having to guess.
Why do New Zealand sandflies bite?
Only female sandflies bite. DOC explains that they use blood to help produce eggs, which are laid beneath stones and plants in flowing water. A bite commonly produces a red, itchy bump or blister. Scratching can worsen the irritation and may damage the skin.
How to prevent sandfly bites
- Cover exposed skin with long sleeves, long trousers, socks and closed shoes.
- Apply a suitable insect repellent to exposed skin and follow the label directions.
- Keep tent and campervan screens closed, especially near bush and water.
- Carry repellent on West Coast and Fiordland walks rather than assuming it will be available at remote stops.
Choose light but closely woven clothing where practical. Long trousers or pants, socks and sleeves reduce exposed skin. Reapply insect repellent only as directed on its label, particularly after swimming or heavy sweating. Parents should check age restrictions and application instructions before using any product on children.
What to do after a sandfly bite
Avoid scratching. Healthify New Zealand advises that ordinary insect bites can generally be managed at home with measures such as a cold pack, aloe vera, paracetamol or an antihistamine, depending on the person and the product directions. Ask a pharmacist if you are unsure. Call 111 for symptoms of a severe allergic reaction, such as difficulty breathing or swelling of the face or throat.
Frequently asked questions about New Zealand sandflies
Do sandflies carry disease in New Zealand?
The usual problem for travellers is the local skin reaction and itch rather than a travel-related disease. Seek medical advice if a bite becomes increasingly painful, hot, swollen, produces pus, or if you feel unwell.
Can sandflies bite through clothing?
Covering up is recommended by DOC because it reduces accessible skin. Very loose or open-weave clothing may offer less protection, so combine clothing with repellent on exposed areas.
Are New Zealand sandflies the same as beach sand flies?
The everyday name “sandfly” is used for different insects around the world. In New Zealand, the biting insects travellers call sandflies are native black flies associated with flowing-water habitats.
Official information
- DOC: mosquitoes and sandflies
- DOC: Fiordland National Park visitor advice
- Healthify: insect bites and stings
Information checked in October 2026. This is general travel information, not individual medical advice.