The Ministry for Primary Industries team at the Auckland port is keeping the country free from a $3.6 billion economic and agricultural catastrophe.
Already tens of thousands of vehicles have been turned away at the border after infestations were found.
A recent boom in the stink bug has seen the team at the Auckland port's attention diverted to the harmful critters.
Lee Umbers reports from the frontline.
I'm reporting from the front line in the war against a voracious foreign invader.
Sure the foe is only 1.7cm long, but it packs a pungent punch.
And it's feared an incursion by Halyomorpha halys – aka the brown marmorated stink bug (BMSB) - could devastate our agriculture, cause billions of dollars of damage to our economy, and overrun Kiwi homes.
I'm at the Auckland port, where giant cargo ships carrying thousands of vehicles from Japan have been turned away in recent weeks after it was found they were infested with the stink bug.
With me is Erin McElhannan, who spearheads a Ministry for Primary Industries
team meeting the threat head-on and successfully helping keep out the sneaky pest designated one of the top five unwanted bugs in New Zealand.
Their campaign is a "war" says McElhannan, MPI's chief quarantine officer for Auckland port.
"We're putting a lot of man hours into trying to keep it out."
"My life has been BMSB since February. For six weeks probably, this is basically all I've been doing."
The at-times 14 strong Auckland-portside MPI team is "passionate" about safeguarding Aotearoa.
The stink bug was first detected in 2012, she says, on ships with cargo from the US. And vehicles coming from Japan have been tested for them for years. But no significant threat was detected until the recent discovery of an infestation on a bulk carrier from Japan.
Scientific advice is that warmer temperatures may have caused population booms in the bug, which is native in several Asian countries.
"That's what they think's happened in Japan," says McElhannan.
Nearly 600 stink bugs, 12 of them alive, were found on one vessel anchored near Auckland in February. It was ordered to leave New Zealand.
McElhannan's team of quarantine officers, headquartered near the entrance to Bledisloe Wharf, are a first line of defence. Armed with torches and other detection devices, they board vessels suspected of containing the bug, and carry out surveillance on the decks.
Stink bugs hide "everywhere", including collecting in large numbers in hidden compartments in vehicles. They "aggregate during the winter months, they're trying to find warm places".
Cargo vessels entering Auckland Port are inspected by MPI officers. High-risk vessels get enhanced levels of surveillance and are likely to be fogged with insecticide to bring bugs out of hiding and kill them, before a further inspection.
Carrying out that fogging is a trained team of biosecurity technicians from biosecurity company Genera Ltd.
A detailed plan of action is drawn up before engaging the stink bugs.
A risk analysis is done and technicians are escorted through each deck and level of the huge vessels – which can have 10-14 cargo decks, each 90,000-150,000 cubic metres, with the capacity to carry 4000-5000 vehicles per ship.
"Basically once you start applying the fog, it's kind of like pea soup," says Genera's
Auckland operations manager Brendan McDunphy.
"You have to work an exit strategy from each deck… work how you're basically going to fog your way off the vessel."
"When you've finished a deck, you cannot see your hand in front of your face."
An MPI-prescribed insecticide is mixed with a fogging agent in a thermofogger – which looks to the untrained eye (ie mine) remarkably like a proton pack gun from the movie Ghostbusters.
The mix sprays from the end of the thermofogger's heat tube, filling the decks and seeping into nooks and crannies to drive any stink bugs out of hiding.
There's a minimum six-hour stand down period after the specially-suited technicians leave the vessel, followed by at least another four to five hours for the areas to ventilate.
MPI officers go back on-board to re-inspect and determine the ship's fate.
For a "medium-risk vessel", such as one which has only visited a Japan port or is carrying perhaps a small amount of freight from Japan, MPI will inspect the ship then may allow a sample to come off the vessel to be further risk-assessed, McElhannan says.
That cargo sample "could be 50, 100, 200 cars, whatever we think is representative enough".
This is where the truly dogged defender of our shorelines joins the fray.
Golden labrador Georgie is New Zealand's first and only dedicated brown marmorated stink bug detector dog.
Wearing socks so she doesn't scratch the vehicles, Georgie will sniff around them for any scent of the bugs.
If she finds a trace, "she'll put her nose on the area that it is, and sit. And then she'll pinpoint exactly where it is", says MPI chief canine trainer Alan Willox.
Her reward - "she gets a biscuit or [a play with] a toy".
Georgie's nose is so sensitive to the bugs, "I've found her to pick them up 2-3 metres away".
The 5-year-old labrador had been working as an agricultural detector dog at Auckland airport, when she was brought into the battle against the stink bug.
With no live bugs to work with in New Zealand, MPI arranged with counterparts in the US, where the pest has become established, to trial two detector dogs there to find out whether they could sniff the pests out.
When that was successful, Willox arranged for the importation of 1000 dead frozen bugs. Thawing 2-4 out at a time he taught Georgie to find them – "condition [her] to the odour".
After two months' training, she began work at the Auckland port – where she's a hit with staff.
"They love her," says Willox, with whom Georgie lives. "But she's a working dog… she's there to do a job."
Georgie will soon be joined on the wharf by other dedicated watchdogs.
A pointer-cross and a crossbreed are training as bug detection dogs, and another labrador is being assessed for training.
Georgie has tested hundreds of vehicles, detecting traces of the bugs in "20 or 30". Sometimes the scents are residual, where fumigation has driven bugs out of vehicles to perish elsewhere in the ships.
Vehicles Georgie identifies are moved further along the wharf for potential remaining pests to have the heat put on them – literally - in Genera's heat treatment chamber.
This can fit three saloon vehicles, two SUVs or one truck at a time.
The chamber is sealed, and hot air circulated throughout it and into the vehicles through ducts. Once the coldest part of the vehicle reaches 60 degrees celsius, a 10-20 minute run begins, depending on the size of the vehicle.
Heat treatment – which does not involve chemicals, and does not damage the vehicles - is deadly for the stink bug.
"Once you start getting over a certain temperature, into the 50s, the heat causes the protein in cells of insects to break down," McDunphy says. "The cells rupture and they dehydrate, basically – that's what kills them."
The treatment can be viewed on a laptop at Genera's office. Sensors monitor the vehicles throughout and data on each is collated and graphed.
These records are available for MPI, whose officers search the vehicles and the chamber for dead stink bugs after the treatments.
Around 600 vehicles have been put through the heat treatment chamber in the past month.
MPI has managed to hold the line against the stink bug so far.
None are known to have made it out alive from the port. Around 2000 dead ones have been sent to the ministry's laboratory at East Tamaki for identification and destruction.
The campaign against the pest has disrupted shipping operations and scheduling.
"Usually a ship coming in would take on average 12 to 24 hours to disembark. And some of these [ships undergoing testing] have been up to nine days," a Ports of Auckland spokesperson says.
"But we are working very closely with the shipping lines and with MPI, and everyone understands it's no one person or organisation's problem. And we're all working very closely together."
"Everyone is concerned about keeping the bug out."
McElhannan says the car retail industry, which has had its vehicle supply chain disrupted, is also supportive. The industry understood "what we're doing and why we're doing it".
The threat the little shield-shaped pest poses can't be underestimated.
Brown marmorated stink bugs attack crops including citrus, pipfruit, stonefruit, berries and grapes – severely disfiguring the fruit and making it unmarketable.
An economic report on the impact of a stink bug incursion showed our gross domestic product falling between $1.8 billion and $3.6b by 2038, and horticultural export value falling between $2b and $4.2b by 2038.
The bugs are also a public nuisance risk, invading homes in their thousands to shelter when the weather cools. Some 26,000 were found in one home in Maryland, in the US.
And if they are crushed or disturbed they emit the characteristic unpleasant and long-lasting odour which entomologist Ruud Kleinpaste – in an awareness video for MPI – describes as "think sweaty socks!".
MPI is running advertisements and distributing leaflets with pictures of the bug to help home gardeners and the wider public identify it. Anyone who thinks they may have seen one is urged to ring MPI's pest-and-diseases hotline on 0800 809966.
McElhannan says as a potentially millions-strong amateur biosecurity officer force, we can all help in the war against the stink bug.
In the words of that iconic poster - Your Country Needs You.