The environmental impact of last week's accidental drop of bait laced with rat poison into a lake on Anchor Island, in Fiordland, is believed to be "very low, if any", Department of Conservation Te Anau area manager Reg Kemper said.
About 700kg of cereal bait pellets were being ferried by helicopter to another island nearby when they dropped into the lake on the pest-free island, which was home to the endangered kakapo.
Mr Kemper said yesterday Doc could now confirm all the pallets dropped into the lake.
Investigations had shown the size and depth of the lake meant detecting any levels of the poison would be difficult due to the dilution factor, he said.
However, samples had been taken and sent away for testing.
"We are confident the environmental impact is very low, if any."
Two kakapo, removed from their home near the lake after the spill, were still on Chalky Island and would remain there while the island was being monitored, he said.
An investigation into the cause of the incident was ongoing and would take a "few weeks", Mr Kemper said.
Doc was working with Environment Southland regarding the incident and the rat eradication programme would not resume until the investigation was complete, he said.
