'Sleeper pests' are everywhere, including children's pets, the New Zealand Biosecurity Institute says.
Institute vice president Darion Embling said it was no longer just mammals such as possums, ferrets, cats and rats causing problems to our native flora and fauna.
Now, New Zealand was being threatened by newer introduced pests, such as sulphur-crested cockatoos and Indian ringnecks, as well as pest fish, aquatic plants and invertebrates such as the guava moth.
He said gardeners should take particularly interest.
"Gardeners need to be very aware of what they're growing, in particularly around dumping, so what do you do when you clean up your garden - make sure that people wisely put your plants in secure places, on the property or in secure refuse centres and places like that. "
Medicinal-type plants were also a threat.
"What happens is these products often get brought into the country, not sure how, as dried products and when these guys have finished with it they have a little bit left over in the bowl or jar and they seem to throw it out the window. And the next rainy period that comes along, it gets re-hydrated and then away it goes."
Pet owners also needed to be aware of the risks of having pets, he said. Turtles and bearded dragons in particular were a risk to New Zealand's invertebrate life.
"I guess for me the key message is if you see something that looks out of place or different, out in your garden, out on your farm, then tell somebody, even if it seems like it's something that's quite small in numbers."