Providing kiwi and other rare native species with a predator-free habitat is costing Waikato ratepayers $10 million-plus.
Supporters of the ambitious 3400ha Maungatautari Ecological Island Trust say the $26 million spent on the wildlife sanctuary - the first in New Zealand, ringed by a 42km pest-proof fence - is a worthy investment to protect kiwi, takahe, hihi, yellow-crowned kakariki and other endangered species.
However, critics fear ratepayers will continue to be lumped with the bill, which should have been picked up by corporate sponsors scared away when a controversial new governance structure was introduced in 2010.
The project's two local government funders - Waikato Regional Council and Waipa District Council - have invested $5.94 million in the sanctuary since 2004, according to information provided under the Local Government Official Information and Meetings Act. The councils have committed almost a further $10 million to the project in the next 10 years.
The Department of Conservation has also contributed $900,000 in the past three years towards the island's $1.5 million annual operating costs.