Thousands of possum tails have been spotted on roads around West Auckland and north of the city.

Mystery surrounds thousands of possum tails dumped on west and north Auckland roads during the long weekend.

The tails littered the roads throughout West Auckland, Nor-West Auckland and reportedly as far north as Dargaville on Sunday.

The fresh-looking tails appeared to have been removed cleanly from possums and dumped at regular intervals along the middle of suburban and scenic roads as well as main highways.

SUPPLIED Authorities say they have no idea where the possum tails came from or the dumper's motive.

Perplexed locals took to Facebook and online forums to discuss the strange event.

A motorcyclist travelling from north of Dargaville to Wellsford on Sunday said he saw what looked like thousands of tails during the two-hour journey.

Another who rode from Wellsford north of Auckland to Kaukapakapa also noticed hundreds of the possum parts.

SUPPLIED Dozens of people have reported seeing the evenly spaced tails in the middle of the road.

Meanwhile, locals in areas including Glen Eden, Titirangi, Muriwai, and Waimauku took to community Facebook pages to report sightings of the tails.

Diane Garaway said she saw at least six tails along the middle of West Coast Rd by the Glen Eden shops.

"Oh my goodness, it seems West Auckland is littered with them," she said.

Others said they had also spotted them on roads in West and North-West Auckland including on Don Buck Rd, Swanson Rd, Sturges Rd, Palomino Dr and Scenic Dr, among others.

Dozens of locals took to social media to report sightings and one person said they had alerted police but police, Fire Service and the Department of Conservation all said no one had reported the bizarre occurrence.

New Zealand Transport Agency (NZTA) spokeswoman Sarah Azam said sightings of possum tails on State Highway 12 in Northland were reported to NZTA on Saturday, then again on Sunday.

On Saturday only the ends of tails had been left on a stretch of Northland road, she said, adding that on Sunday whole tails had been dumped along the same stretch of highway from Ruawai to Maungaturoto.

NZTA contractors were called on both occasions to clean up the tails, Azam said.

"Obviously, our job is to keep the roads hazard-free and they are a distraction as much as anything."

Contractors said the tails were spaced about 50 metres apart along the 20km stretch of road.

NZTA had not been notified of tails being dumped on other roads in the wider Auckland region, she said.

It was the first time the agency had dealt with an incident like this as far as she was aware.

Rodney Local Board member Phelan Pirrie said there had been speculation about where the tails came from and why they had been dumped on Auckland and Northland roads.

However, no one had solved the mystery.

There were various theories floating around that it was a protest to the use of 1080 to kill possums but it was unlikely as no one had claimed responsibility, he said.

Waitakere Ranges Local Board member Neil Henderson said he was baffled by the tails.

"It's absolutely bizarre."

The high number of tails meant it was likely to involve someone in the possum fur business.

However, he would have expected the tails to be kept on the carcasses so their fur could also be sold.

Possum fur sells at about $110 a kilogram and it can take up to 20 possums to make a kilogram of fur.

Henderson said while he did not know the person's motives, the possum tails highlighted issues with the growing possum population in the Waitakere area.

In recent years Auckland Council had cut biosecurity funding to West Auckland, he said.

Henderson said he planned to use the mysterious tails to raise awareness on the subject.