A Far North conservation group is urging the council to allow qualified locals to oversee any future roadside weed control after what they say was ''random and indiscriminate'' spraying on the Russell Peninsula.
David McKenzie, chairman of Russell Landcare Trust, said recent spraying seemed to have been carried out by someone who didn't know the difference between native plants and weeds.
In a similar controversy in Waimate North, pōhutukawa planted in a volunteer project 20 years ago were sprayed.
The spraying has, however, been defended by the Far North District Council, which says sprayed natives were overgrown with weeds and branches on some young kauri were dying off for other reasons.
McKenzie said the native māpou had been specifically targeted all the way from Okiato to Russell, and many kānuka and mānuka had been sprayed along with tree ferns, young kauri and tānekaha.
''Yet the weed species that should have been sprayed — such as gorse, pampas, tobacco plant, jasmine — were missed or only partly sprayed,'' he said.
He had also seen spraying at Orongo Bay and Matauwhi Bay where the verges were close to the sea, raising concerns about chemical run-off.
Landcare members had been working for nearly 20 years to restore Russell's native biodiversity, he said.
''So it's devastating and infuriating to see such careless action undo all this effort in a few hours. We'd like to see the natives replanted and dead vegetation, which could be a fire hazard, cleared.''
McKenzie said he had previously approached the council to ask if Landcare members, who were qualified to handle herbicides, could weed spray roadsides.
He was told the council couldn't sanction the use of volunteers because of health and safety issues, but he believed now was a good time to reconsider whether community groups could advise and oversee contractors on the council's behalf.
It would also provide local employment, a key plank of the government's Covid recovery response, McKenzie said.
The spraying was part of a Government Covid-19 employment recovery programme. The Far North initially received $2.2m for public works but that was boosted to $4.4m after the July storm.
Work carried out included roadside weed spraying, removal of hazardous trees, picking up roadside litter and building new footpaths.
Council infrastructure manager Andy Finch said roading contractor Ventia subcontracted the work at Russell to a qualified and experienced contractor.
The target species were pest or invasive species already on the council's spray list, but Covid recovery funding had enabled extra work on tourist and high-volume routes.
After public complaints, council staff, a Ventia manager and the contractor inspected Aucks Rd, Russell-Whakapara Rd and Florance Ave.
Finch said the normal 2m-wide spray envelope had been increased to 4m to improve sightlines and road safety. The expanded spray footprint had included self-sown tōtara and other native trees.
A small kauri was sprayed on Aucks Rd but staff were confident it was self-sown and not part of a community planting project. A pōhutukawa was sprayed because it was growing in front of a culvert and would eventually block stormwater flows.
A sprayed mangrove was overgrown in Himalayan honeysuckle, one of the target species, but the mangrove was expected to survive.
The inspection found brown-off and die-back on community-planted kauri but similar signs were seen on kauri well away from the road. The discolouration was thought to be because kauri naturally shed branches as they grow.
''Unfortunately, it's inevitable that incidental spray drift will occasionally affect nearby non-target vegetation. The council is mindful of this and works with contractors to reduce these incidents wherever possible.''
No more weed spraying was planned in Russell this summer, he said.