The New Holland mouse is primarily threatened by alteration and loss of suitable habitat. At first the loss of habitat was mainly caused by clearing, but now frequent fires and predation by the introduced red fox and cat are potential threats to this species. The species was regarded as rare when it was discovered in 1970, many of the areas that once supported the New Holland mouse now have small to nonexistent populations of this species. The Scientific Advisory Committee determined that "(1). New Holland mouse is in a demonstrable state of decline which is likely to result in extinction; and (2) very rare in terms of abundance or distribution."