The Northland Regional Council (NRC) is seeking answers after two dead wallabies were spotted on the region's roads this month.
One dead wallaby was found on the side of the highway near Kawakawa and a second was reportedly seen on the road just south of the State Highway 1 Maungakaramea intersection a few days later.
The council warns it could pose a serious biosecurity risk to the region.
NRC biosecurity manager Nicky Fitzgibbon said the council was alerted to reports of the first dead wallaby on December 4, on the side of SH1 near Kawakawa's three road bridges.
"Two council staff had spoken to the man who had discovered the wallaby but unfortunately by the time report came through the animal had been fed to some dogs and there was no trace left of it," NRC said in a statement on Thursday.
Due to torrential rain, there was nothing to indicate the pest had been struck by a vehicle.
"On considering all the evidence and speaking with the members of the public who reported it, staff are confident the report was genuine and the animal was a wallaby," Fitzgibbon said.
Live wallabies are unwanted in Northland because they eat native and exotic seedlings and pasture; making them costly to the farming and forestry sectors and posing a risk to native bush too, as they can limit the regeneration of some species, the statement read.
They are formally classified as an "exclusion pest" under the council's Regional Pest Management Plan due to the serious environmental, economic and other risks they pose.
Fitzgibbon said cameras have been set up at two properties in the wider area as a precaution but the terrain surrounding the site where the wallaby had been found was not likely to be suitable for the animal.
The council believes the dead animal could have been killed elsewhere or fallen from a moving vehicle.
Wallabies are found on Kawau Island, just south of Northland Regional Council's boundary, and large numbers are present in the Rotorua Lakes, north Otago and south Canterbury regions.
Fitzgibbon said adding credibility to the council's theory the wallaby may have fallen from a vehicle was the reported sighting of another wallaby carcass on the road just south of the SH1 Maungakaramea intersection on December 11.
She's urging anyone with information to come forward, including people who may have been transporting dead wallabies into Northland or who had seen a vehicle doing so.
Any sightings can be reported online at www.reportwallabies.nz.
