Killing and trapping doesn't even scratch the surface of the problem, it is truly immense. Rabbits have no native predators in NZ and they breed like... well, r

Killing and trapping doesn't even scratch the surface of the problem, it is truly immense. Rabbits have no native predators in NZ and they breed like... well, rabbits. There has been huge amounts of debate, research and approaches taken to reducing their numbers, some more controversial than others (e.g. have a look at the ongoing debate around 1080 poisoning). The introduction of a virus is not something that is done lightly here. Bear in mind that NZ has one huge advantage compared to most countries here in that the only native land mammal is a bat, so there's not a big risk of the virus spreading across to other native species (this is the reason why 1080 is effective too as it generally only kills mammals). Note that the myxomatosis virus was introduced (illegally) by farmers to NZ in 1997 and it proved pretty effective at reducing the rabbit population for the next 10 years or so, until resistance built up.