Peanut, since you are staff, you can find the NIWA's discussion
here.
Several methods were discussed and applied. These methods are not too hard to guess, but, I'm not sure if I should speak them here since it's hidden for a reason. If you have a question, put it in the thread.
For those who are not staff, talk to a staff member of your wiki, since each wiki had a different method or combination of methods to deal with the issue.
To answer you question, a lot of the NIWA wikis have indeed been hit.