The New Zealand Threat Classification System report on the conservation status of New Zealand bats updates the last review in 2012.
The most significant change is the move of southern short-tailed bat from 'threatened' to 'recovering', largely due to DOC's sustained control of rats, possums and stoats in its last mainland habitat, Ms Sage said.
"Numbers of short-tailed bats in the Eglinton valley in Fiordland National Park have steadily grown from about 300 to more than 3000 since predator control began more than a decade ago."
The Eglinton is the last known South Island mainland site for this bat subspecies, which is also found on pest-free Whenua Hou/Codfish Island.
The population of long-tailed bats in the Eglinton is also growing at a similar rate.
The picture is not as good for bats in other areas, particularly the North Island, Ms Sage says.
"The status of our North Island long-tailed bats has worsened since 2012 and they are now grouped with their South Island counterparts in the highest threat category of 'nationally critical'."
Previously the North Island long-tailed bat was assessed separately as being in a lower threat category but new genetic research has confirmed just one species.
The new threat assessment confirms that where bat forest habitat is safe and predators are suppressed, our only native land mammals can recover.
"Yet in many areas populations of both bat species continue to decline due to the threat of rats, stoats, possums and cats, and clearance of lowland forest and large old trees where bats roost."
The effects of wasps and potential effect of kauri dieback on roost trees is also of concern.
New Zealand has two species of bats—the long-tailed bat and short-tailed bat, of which there are three subspecies. A third species—the greater short-tailed bat—is thought to be extinct.
The threat status of the central and northern short-tailed bat subspecies (found in the central and northern North Island) remains the same as in 2012—both are declining.
Bats can fly up to 30 kilometres from their roosting areas to forage and a colony range over more than 100 square kilometres. This can make them seem more numerous than they actually are.
Conservation status of New Zealand bats, 2017 (PDF, 1062K)