A group that opposed a 1080 drop has been ordered to pay Auckland Council and the Department of Conservation over $40,000 in costs after the Environment Court found its case was "legally without substance".
The Friends of Sherwood Trust went to the Environment Court in September last year challenging a 1080 poison drop in the Hunua Ranges, and won a court injunction temporarily suspending the operation.
The court later threw out the case, stating: "We are not persuaded that there is likely to be serious harm to the environment if the proposed application proceeds."
Now the trust must pay over $40,000 in court costs.
In seeking costs both the council and DoC submitted the arguments put forward by Friends of Sherwood were "without substance" and their case was "poorly presented".
In her decision Environment Judge Melanie Harland said the court agreed.
"The applicants did not provide the necessary admissible proof to support their case about adverse effects," the decision read.
Most of the evidence filed was "opinion but not expert evidence", or there was insufficient information about the context to the alleged adverse effects or historical events.
The court took into account the view of Friends of Sherwood that it represented a view of some members of the community about the use of 1080 for pest control.
"However it is just that - one view," the decision read.
That view was "comprehensively met" by the evidence from the council, DoC and the Public Health Service, who arguably also represented the public interest.
The arguments advanced by Friends of Sherwood were "legally without substance and the evidence about potentially adverse effects was evidentially problematic".
The judge also acknowledged the costs of the council and DoC were met by the public.
"Because this case concerned an application for interim enforcement orders which was required to be dealt with as a matter of priority, it was incumbent upon Friends of Sherwood to present an evidentially sound and legally sustainable case to succeed.
"For the reasons we have expressed above, it fell well short of the mark in this regard."
Friends of Sherwood was ordered to pay the council $22,826 - 50 per cent of its fees - and DoC $19,451.08.
The Environment Court declined the council's application for costs from the Ngāti Paoa Trust Board, a joint applicant in the case but which was primarily concerned about consultation.
The operation went ahead over September and October, and involved dropping sodium fluoroacetate (1080) by helicopter to 30,501ha across the ranges, an area that provides about 65 per cent of Auckland's drinking water from four large water reservoirs.
The Auckland Regional Public Health Service had developed various safety measures for the drop.
The council and DoC planned the 1080 drop to reduce pest numbers and maintain the natural habitat of the Hunua Ranges in an area known as Kohukohunui. Pest levels had risen again after a successful 2015 operation.
In February the council reported the operation had reduced pest numbers to their "lowest-ever" levels, and led to a doubling of kōkako breeding pairs.