Queenstown Lakes District Council arborist Tim Errington said a contractor spotted the branch on the ground near the Lake Wanaka willow just before Christmas and reported it to the council.
Mr Errington said for the size of the tree it would have been a big branch and because the tree was so compact and had such a slow growth rate, it needed all its foliage to survive and photosynthesise, so any reduction could be quite disastrous.
The Wanaka lake tree was most likely a crack willow, which was one of Britain’s largest native willows, but was stunted due to its growing conditions in a lake.
Willows in general were "pretty tough" but could be damaged very easily as their bark was particularly soft and easily dislodged.
"So, if people clamber over the tree, it would be very easy to kick off a section of bark, which isn’t good as it is an entry point for disease and decay."
Staff discussed building a fence around the tree, but decided instead to put up signs in both English and Mandarin, asking people not to climb the tree.
"The tree is in a semi-wild location and that’s what people come here to experience, and we felt if you build a fence around it it takes away from that."
If there was any more significant damage, other options might be considered.
The popularity of the tree went global following an "instameet" in 2015, attended by more than 100 people internationally known instagrammers.
Since then, the hashtag #thatwanakatree has been used 18,500 times.
Wanaka i-Site manager Jaimee McGrath said "Where is the tree?" is one of the questions most commonly asked by tourists.
She said people did not always know what it was, but had been told they had to see it.
Yesterday, Russian newlyweds Vladimir and Natasha Zaidsev, who were married in Russia in December and are honeymooning in New Zealand, having "wedding" photos taken around the country, were having pictures taken at the tree by Auckland photographer James Hirata.
