Thirteen weeds have been identified as priority targets for eradication in order to protect indigenous biodiversity.
Wilding pines spread near Lake Pukaki. Photo: MPI
The government last year declared 'War on Weeds', and another $16 million has been allocated in this year's Budget to control the spread of invasive species over the next four years.
Number one on the list is wilding conifer (wilding pines); others which are new to the list this year include Japanese honeysuckle and Darwin's barberry.
Darwin's barberry is an invasive plant of particular concern in the lower South Island - it replaces shrubland and regenerating forest and can be transported long distances by starlings.
Japanese honeysuckle is a popular garden plant, but one which forms dense masses which smother natives.
Conservation Minister Maggie Barry said wildings cover 1.8 million hectares of land and are advancing at the rate of about 5 percent a year.
She said they transformed entire landscapes, ruined native ecosystems and took over productive land.