Feral rabbits in Auckland Domain could be shot, and a rabbit dog and pest baiting are already set to tackle the animals.
Auckland Council plans to invite a regular canine guest to the city's oldest park, with the first rabbit-hunting dog scheduled to visit in early August.
The council said pet owners dumping the animals had most likely created the problem population.
David Stejskal, the council's Regional Arborists and Ecological Manager, said the Domain's botanical importance meant eradicating the rabbits was imperative.
The hunting dog will visit about once every three months. An anticoagulant bait will also be deployed, Stejskal said.
"Small-scale pindone baiting has previously been a successful measure and this will be employed again."
Predator Free NZ described Pindone as being effective on rats, rabbits and possums. The antidote for it is Vitamin K2.
If the rabbit population proliferates, or if the animals can be confined to a small area, the council might shoot them at night-time.
Any pest management using firearms involved professionals with specialised equipment, and under police notification when parks were closed, Stejskal added.
He said members of the public weren't allowed to use firearms in public parks, because of safety risks.
Stejskal said alternative killing methods could involve poison, which also presented a hazard and usually required a licence.
"Any other methods would not be legal under the Animal Welfare Act or Biosecurity Act."
The council estimated no more than four feral rabbits were in the entire Domain.
But a member of the public saw that many in a few minutes on Monday in just one part of the park near Auckland Bowling Club.
The presence of rabbits in the Domain was raised at a November 2020 council meeting.
"The rabbits took a liking to the annual flower beds and destroyed the recently planted floral displays," the Auckland Domain Committee was told.
The animals have also been dumped in recent years at Western Springs.
The rabbit is endangered in its Spanish and Portuguese homeland but populations elsewhere can quickly reach plague proportions.
New Zealand's first rabbit plague started in the early 1870s and lasted nearly 25 years.
According to DoC, rabbits can survive long droughts, even by eating their own faeces to absorb more nutrients.
The Domain is Auckland's oldest park, one of its largest, and includes a remnant of the ancient volcano Pukekawa.