Sorry, can't help you here.  In natural areas around northeast Ilinois,
two fo the most feared and tenacious and rampant introduced weeds are
sweet clover (Melilotus) and loosestrife (Lythrum).  Both are alwasy
covered with honeybees, and natural areas manageers would do anything
to get rid of the honeybees.
I can't speak for the situation in New Zealand, but it is possible that
the Ntional Park rules might prevent similar weed miseries.
Keep informed.....
Liz Day
presently in New York City, USA
receiving mail at [log in to unmask]
(that's Lday, not ONEday)
(formerly of the Chicago, Illinois, USA area)