A contentious aerial 1080 operation in the Coromandel Peninsula has been hailed as "phenomenally successful" after trapping revealed no possums present in the drop area.
Monitoring results from the Papakai and Moehau possum control work, which was done six months ago, indicated a complete absence of possums in the patches of bush that were treated.
Protesters attempted to disrupt the Moehau operation, but the Department of Conservation has declared the results of the drop "outstanding" and downplayed the opposition.
The data comes as the Environmental Protection Authority (EPA) released a five-year review into 1080 use, which showed complaints about it had declined although it revealed Waikato residents to be the most vocal opponents.
DOC partnerships ranger Greg van der Lee, who helped in the operational planning of the two Coromandel drops, said they were "phenomenally successful".
At Papakai, the monitoring lines showed no possums or rats were present.
No possums were caught in the trap monitoring lines at Moehau either - despite a substantial possum presence before the operation.
Mr van der Lee said as the results were based on statistical modelling they were open to interpretation, but they were "as good an indication as we have".
He expected the operations to have a positive result for native wildlife.
"Going on past experiences we have had up to a 100 per cent increase in the [bird] hatching rate."
About 10 people gathered at Stony Bay to protest against the Moehau operation this year, but Mr van der Lee said the opposition was insignificant.
The EPA's five-year review shows complaints have declined markedly between 2008 and 2012. But residents in the Waikato complained about 1080 operations more than any other region.
That figure correlated to the quantity used (883kg over five years), which was only second behind the West Coast region.
In 2008 there were 12 complaints about its use in the region, but that figure had dropped to just 2 by 2012.
On average, about 63,000 hectares of land in the Waikato region has been treated by 1080 each year.
Nationally the quantity of poison used dropped by almost a third between 2008 and 2010, but has remained relatively constant since.
The review also dismissed fears over how 1080 affected water quality.
"There was no evidence that 1080 adversely affected aquatic species or persisted in water," the report said.
Monitoring showed that 1080 was detected in only two per cent of all samples and has never been detected in drinking water catchments.
The report concluded 1080 was the "only viable option" to control pests.
- Waikato Times