Ongaonga has tropical names like timor, java and the devil leaf. It is a dangerous plant so stay away from it. Ongaonga is also named Urtica ferox. It is found on the west coast of the south island and north of Auckland and Otago. It’s rare. You could die if you fall into one of these. It has killed several dogs, horses, a guinea pig and at least one tramper. If you do get stung by one or two of the hairs it won’t do much harm but leave bright red patches on your arm or back.
How to heal it. Crush some leaves from the Kawakawa tree. Rub them on the area that it has been stung.