Portuguese millipedes infesting Wellington, entomologist says

1News

24-04-2025

An entomologist says the spread of Portuguese millipedes across Wellington — and beyond — is almost certain after residents on the south coast sounded the alarm about infestations of the invasive species.
Residents have described waking to find hundreds of scaly black millipedes around their homes, discovering them in shoes, bags and even their beds.
Biosecurity New Zealand said the invertebrate had been identified on the south coast and in Lower Hutt for about 20 years, but not much was known about it.
A local councillor is now calling for an urgent meeting with local authorities to discuss how to tackle the problem.
Chris Picking, who has lived on Wellington's south coast for 15 years, told Morning Report he first noticed the millipedes a couple of years ago, but since then the population has exploded.
"There's hundreds or maybe thousands I have to clean up around the house every day."
He said he had found them in every nook and cranny, and they were particularly active at night.
"We've had them in the lounge, in the bed, we've had them crawling on the dog, hanging from the walls and the ceiling.
"I've had one on me in the bed [and] I've woken up and it's been on my face. Anywhere you can think, I've seen them."
For a few weeks a year when the population spiked, Picking said keeping the infestation at bay was a daily mission.
"The only way to get rid of them is to put poison down and squash them... and when you squash them, they're pretty nasty," he said.
"They exude this toxic smelly stuff."
When RNZ visited Te Kopahou centre at the entrance to Red Rocks on Wednesday, millipedes could be seen marching along the ground next to hundreds more that were curled-up, dead.
On community social media pages people report millipedes in Island Bay and Southgate.
One person said they were seeing "multitudes" on Buckley Road, while another on Happy Valley Road said the house had been "swarmed by millipedes for weeks".
Professor of entomology at Victoria University Phil Lester said it was "almost certain" the millipedes would move beyond the current affected suburbs.
"It's a problem that's only going to get worse, I suspect, and they are probably going to like Wellington, and a large part of New Zealand, very much."
He said the creature, which was attracted to light, emerged from the ground to breed in autumn, which was why residents were being particularly plagued now.
However, he said controlling the population would be difficult, and it likely wouldn't meet the threshold for pest management until more people were affected.
In Australia — where millipedes were blamed for a train crash in 2013 — a viral nematode helps control the population, Lester said.
He said a biological control agent was probably one of few options for New Zealand, but said the method came with risks to native species.
Biosecurity New Zealand's acting assistant commissioner of compliance and response Chelsea Bridgman said the millipede had been identified in Seaview, Gracefield, Wainuiomata and Owhiro Bay.
"We know very little about the ecological impact of Portuguese millipedes on New Zealand's native flora and fauna, as the scientific literature is unclear. The millipede mainly feeds on decomposing organic matter," Bridgman said.
She advised homeowners to remove green waste from gardens and create physical or chemical barriers around doors and windows.
On it's website, Greater Wellington Regional Council stated that while the millipede was a nuisance, it was not a risk to human health and was not known to have any negative effects on the environment.
Acting environment group manager David Hipkins said the species was not listed as a pest in the regional pest management plan, and therefore there was "no mandate to formally monitor populations or undertake control efforts".
However, the council might reconsider, if the population appeared to be spreading, he said.
In response to recent complaints from residents, Wellington city councillor Nureddin Abdurahman has demanded an urgent meeting to discuss how the district and regional councils could better monitor and contain the millipedes.
"As well as being a serious issue for residents affected by the outbreak, I am also concerned about potential ecological damage if the spread is allowed to continue."
Chris Picking told RNZ the response so far from authorities had been disappointing.
"Someone needs to take a look at what's actually happening here."
In the meantime, he said his only option — which he wasn't keen on — was to continue spraying poison around the perimeter of his house.
By Mary Argue for rnz.co.nz