The New Zealand Plant Conservation Network

This weed has taken over a large patch of Mt Victoria reserve in Auckland, and is now happily colonising our (adjacent) and neighbours gardens. We've twice asked the council to at least take a look, as have some of the neighbours, but they don't seem to be interested. I'm hoping if we knew what it was we could spur them into action - the plants are now 1.5m high in places and are choking out smaller plants.

The stems and leaf veins have tiny white hairs on them, though the leaves themselves don't.
The stems don't appear to be hollow, and are green with a reddish tinge towards the base.
The roots may be a tap root with smaller fleshy roots coming off just below the ground - I'm not sure if I've managed to get a whole root system out yet.
Leaves are about 30cm on the bigger plants, maybe bigger.

Any help appreciated and I can provide more info if you can tell me what to look for.

Hi Michael, the plant looks more like Acanthus mollis (bear's britches), but hard to be sure without flowers. This is not a major weed, but can be a local nuisance when it forms dense patches in damper or shaded areas. It has a very persistent root and the only control method I'm aware of is digging out the roots and putting them through a mulcher

Hi Mike, I looked up some photos of Acanthus mollis and I reckon you nailed it, thank you. Sounds like a hard plant to get rid of.