Dealing with New Zealand sandflies – a survival guide

These tiny creatures can ruin anyone's holiday, here's how to cope

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As an American with limited options for a working holiday visa, I chose New Zealand over Australia for a few key reasons.

One, of course, was the draw of the majestic Southern Alps, a truly magnificent spectacle without comparison. The other was because I really don’t enjoy stifling hot temperatures. The third and perhaps the most compelling argument against Australia was that there are too many things to kill you. Spiders, snakes, crocodiles. Even the kangaroo, which Winnie the Pooh led us to believe was kind and nurturing creatures have their dark side. (Seriously have you seen a buff kangaroo trying to drown a dog!?)

With a mild climate and nearly predator-free backcountry, it was an easy choice for me when I weighed my pros and cons but there was one I missed. One creature that feeds on human blood so viciously despite its pint-size stature.

The dreaded sandfly.

sandfly New Zealand
Not pictured: 1 million sandflies

If you have spent time in the South Island, you know what I’m talking about. In fact, you’re probably nodding along right now, groaning in agreement, thinking back to all of the awful bites you’ve endured.

These little blood-sucking devil creatures are, at best, 3 mm long, about a 1/3 size of your average mosquito. They look like little gnats or flies for my fellow Americans, and they congregate in the most notoriously beautiful places of New Zealand, the pristine wilderness around Fiordland and the West Coast.

It’s super easy to poo-poo them off as a slight annoyance, but these little bastards are not to be taken lightly! If you’re coming to New Zealand, it’ll serve you well to be mentally and physically prepared to take on the small, but mighty, sandfly so start prepping!

Here’s everything you need to know about sandflies in New Zealand and how to survive them.

They are ruthless bloodsuckers

Out of the 19 sandfly species in New Zealand, only three of them bite but these three species cover most of the country, sparing only a few dry areas on the South Island’s east coast.

Despite what it seems like, sandflies don’t bite just to be annoying. They need a healthy dose of human and animal blood and they’ll hop across any exposed skin until they find their blood meal. These cheeky devils prefer to feed at dusk, conveniently just as all the tourists are flocking to the outdoors to catch one of New Zealand’s stunning sunsets.

It’s New Zealand’s oldest tourist trap.

sandfly New Zealand

Females are savage

Like mosquitos, female sandflies are doing it for themselves. And by that I mean only female sandflies are the biters but they don’t go around biting all willy-nilly just to have a good time. They need the blood for valuable reproductive nutrients.

Without a blood meal, female sandflies can lay up to 12 eggs but with just a SINGLE drop of the protein-ridden human blood, she can lay 10 times that number, passing on her legacy to thousands of little bastards.

These modern-day, progressive lady sandflies are not waiting for any man sandfly to provide nutrients. In fact, male sandflies remain a complete mystery, providing almost no use other than to provide reproductive needs.

No one in New Zealand has ever seen a male sandfly feed. They tend to be a lazy bunch who emerge from their pupae at the same time as the females but then they disappear shortly after. Hello, matriarchy.

sandfly New Zealand
Gotta respect the girl power of the sandlfy.

They pack a small but mighty punch

Unlike a mosquito who can issue a subtle bite not felt for hours, the sandflies draw blood by using their razor-sharp knife-shaped mouth to slice the skin which allows them to promptly lap up the pool of blood.

The bite is sharp and painful (unlike mosquitos, you definitely know when you’re being bitten) but what causes even more pain is the histamine and agglutinins they release into the blood that prevents clotting and prepares the blood for easy digestion.

The presence of histamines makes nerve cells fire repeatedly which our brains interpret as itching.

They also swarm. Scientists have shown they can bit up to 1000 times an hour. Holy shit!

sandfly New Zealand

No, you’re not going to die from a bite

Despite being incredibly obnoxious, itchy, and often painful, a sandfly bite is not going to cause you any harm. Unlike mosquitos, the only disease sandflies have reportedly transmitted is Avian Malaria which only affects birds.

That crystal clear river is a lot more likely to be sandfly ridden than that murky pond: sandflies are named after their color, not their dwelling or habitat.

Contrary to popular belief, sandflies prefer running water instead still water. You’re more likely to find them near a crystal clear river than a stagnant boggy pond. In fact, the most sandflies ridden places are dense forests on the edge of a stream or river.

If you’re headed to the West Coast or Milford Sound, you’re more than promised a few encounters with the little buggers. To avoid dehydration, sandflies dwell in humid environments, such as the West Coast or Fiordland, where humidity exceeds 60 percent.

sandfly New Zealand

Early Maori legend even has it that the god Tu-te-raki-whanoa had just finished creating the landscape of Fiordland, but the landscape was so stunning in beaut that when the underworld goddess Hine-nui-te-po saw the fiord’s beauty, she feared that visitors would never leave, so she released sandflies (namu in Maori) to chase them away.

Brutal but effective.

Basically, sandflies will look for any opportunity to ruin your outdoor experience whether you’re trying to enjoy a peaceful paddle on the Milford Sound or soaking up the benefits from one of the many natural hot springs found through the country.

sandfly New Zealand

Winter is your friend

Winter in New Zealand often gets a bad rap. It’s cold. It’s darker much more often than not. The weather can be fickle.

But one thing winter has going for it is that sandflies are a lot less active.

Sandflies thrive on warm and cloudy days. Congratulations winter, you’ve done at least one thing right.

sandfly New Zealand
Good job, winter.

How to prevent sadly bites

Your first sandfly bite in New Zealand will have you racing to the nearest pharmacy to find itch relief and a good repellent for the next time you’re outside.

There are plenty of options when it comes to repellent, all claiming to be the best at keeping your skin sandfly-free, but they are full of lies. These repellents hardly seem to work unless they are at least 40% Deet, and I’ve always found the sandflies to be far too persistent for any spray.

Since sandflies gravitate towards dark clothing, the lighter your outside apparel is the better your chances of not getting bitten.

Of course, the surest way to protect yourself is to be fully covered. Light but long layers will be your friend if you’re going to be in the bush for long periods of time. Limiting the amount of skin exposed is your best bet, especially the ankles and toes, which sandflies seem to love.

You also will be praying for wind, which blows them away. On windy days you’re much less likely to be bitten.

sandfly New Zealand

My favorite tactic of all time is to keep moving.

I’m not joking you guys. When I’m hiking in a sandfly ridden area on a hot summer day when my layers are short and light, I refuse to stop for long. Of course, I have to stop sometimes to eat or rest but I try to stay moving no matter what.

Have you ever tried walking around in a circle while eating a PB&J? It’s tricky but worth it. For some reason, sandflies take a while to catch on to your exact location so even just a little bit of dancing or walking will help keep you safe. Be a hard target to catch!

Another important tip is to make sure you always leave your car windows and doors shut when driving through sandfly territory otherwise your vehicle will fill with the biting bastards. You’ll only make that mistake once.

sandfly New Zealand

Some people are bitten more than others, who know’s why.

This could be attributed to odor or body heat and how much carbon dioxide each of us exhales. Carbon dioxide is the sandfly equivalent to freshly baked cookies. Once they get within 6 meters of the victim, sandflies switch to visual hunting mode to help locate a suitable landing pad.

Eventually, after continuous re-exposure, the human body’s reaction to the allergen becomes less severe but don’t expect to become immune overnight. It takes about 10,000 bites to desensitize.

Only true hardy bush kiwis can go for the general ignore method with any degree of success. There are theories that eating a lot of marmite can also be effective.

sandfly New Zealand

No, they can’t be eradicated

If you’re holding out for when New Zealand is finally able to get the sandfly population under control, you’d better be prepared to wait for a while.

For a long time, New Zealand was a land with no native mammal predators but throughout time, the Europeans who arrived began introducing pests like mice, rabbits, stoats, and ferrets. Now, the Department of Conservation spends a large chunk of its budget trying to eradicate and manage the pest population. If you’re like me, you’ve probably wondered why the hell haven’t we tried to eradicate sandflies??

The short answer is, we have.

Over the past century, scientists have tried several times to introduce a sandfly predator but to no avail.

The mighty sandfly proves it can’t be killed and lives on, so if you’re wanting to see New Zealand’s remote beauty for yourself, be ready to face the wrath of the sandfly. At the end of your time in New Zealand, you may remember the sting of the sandfly bite but what really stands out in your memory will be the towering fiords, the rushing braided rivers, or the commanding glaciers.

Just cover up. No skin is the only full-proof method.

Have you experienced the tiny but mighty New Zealand sandfly? Any horror stories? Spill!

sandfly New Zealand

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47 Comments on “Dealing with New Zealand sandflies – a survival guide

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  1. I only experienced New Zealand in winter, so I was lucky never to encounter those tiny beasts but I will be coming for next NZ’s summer so I am dreading the encounter.
    What you say about marmite semms to be true – it is rich in Vitamins Bs; which seem to work as a natural repellent for mosquitos too, when found in higher levels than usual in the blood. Let’s get some marmite/vegemite on toast !

  2. Interesting Erica. I swear I didn’t see 1 – or get bitten – during a recent 3 month trip to NZ. But I was there during colder fall months and also covered up like crazy in some windy, chilly spots, so the little guys had zero real estate for biting. Good thing too; during a layover in Australia I recall those flies that went inside your nose and ears being all over me….nightmare. I’d almost rather be bitten LOL.

    1. We went to Curio Bay on Sunday and was almost eaten alive. We went to buy a repellent stick at the little shop but these buggers were determined to eat us alive. That evening I started itching all over my legs andarms. I

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