The public in Wairoa are being warned not to touch rook bait which was lost in the area.
The 10 sealed gel tubes were lost from a helicopter while Hawke's Bay Regional Council was undertaking rook control.
The bag containing the bait, along with jerry cans and some personal items, was attached to the bottom of the helicopter when it was lost.
Searches have been undertaken along the helicopter's flight path, both by air and on foot, primarily farmland, forestry and conservation land.
Landowners in the area, police, Ministry of Health, Hawke's Bay District Health Board, Department of Conservation (DoC) and the Civil Aviation Authority have been informed.
HBDHB medical officer of health Nicholas Jones said it was unlikely to be consumed, as it had likely been lost on steep terrain not easily accessed by the public, was contained within sealed tubes and diluted in a petroleum jelly making it unpalatable.
He said while the bait was toxic to rooks, it was much less toxic to humans, however, should not be handled or consumed.
The items are contained in a black DeWalt bag.
If found, the location should be noted and police informed, immediately, and ensure no humans or animals can access them.
Rooks are considered a pest, and are especially problematic in the farming community, due to their ability to strip crops in a matter of day.
Rooks are highly susceptible to the poison used, DRC 1339, which most other bird species have increased resistance to.