A wasp expert says the area where a man was stung to death by wasps at the weekend has some of the densest populations of the insects in the world.
The man died after being stung multiple times when he disturbed a nest while collecting firewood in Marlborough.
Richard Toft, a wasp expert in Nelson, says fatal incidents are rare, but if someone steps on a nest they can receive hundreds of stings at once.
He says beech forests in the South Island are particularly high in wasp numbers because insects in the trees produce a sugary substance called honeydew.
An Auckland-based exterminator, Peter Erceg, says wasps can form underground nests up to three metres deep, holding thousands of insects.
Mr Erceg says using flyspray on nests will only enrage the insects and it is best to leave them to the experts.