Pest wasps are costing New Zealand's economy $130 million a year, a new study says.

The impact of the introduced pests included wasp-related traffic incidents, costing $1.4 million a year, and more than $1 million in health costs from wasp stings.

But the greatest impact was on farming, beekeeping, horticulture and forestry, the study said.

Wasps disrupted bee pollination, reducing the amount of clover in pastures, and increasing the need for fertiliser, costing the farming industry $60 million a year.


The cost to beekeepers of stopping wasps from attacking honey bees was $9 million a year.

The research was funded by the Department of Conservation (DOC) and the Ministry for Primary Industries (MPI).

DOC Scientist Eric Edwards said as well as the financial cost, wasps also affected tourism, and people's experience of the outdoors.

"It's hard to put a dollar value on people's attitudes to wasps and to what extent wasps prevent them from visiting conservation land or taking part in outdoor tourism activities," he said.

"But we know that wasps are a massive annoyance and their multiple stings can cause a lifetime effect of making young people reluctant to return to forests and parks."

MPI's Erik van Eyndhoven said the study showed it made economic and environmental sense to invest in wasp control.

"MPI is working with DOC to encourage the science community, and their funders, to further explore a range of tools needed to control wasps in the long term."

The MPI Sustainable Farming Fund has supported investigation into a new mite discovered in wasp nests, while DOC has been piloting a target bait station method on conservation land.