An extremely rare costume worn by a "chief mourner" in French Polynesia – which dates back to the 18th century and is valued at $1.2 million – is among Te Papa collection items damaged over the past 18 months.
The national museum has confirmed the ahu parau outfit was damaged while in transit from Wellington to Canberra, where it was to be shown as part of a loan arrangement.
Information obtained under the Official Information Act said the damage to its intricate apron and head dress was likely caused by "excessive vibration".
It was repaired by Te Papa staff, and "several parts" had to be reattached.
Te Papa said of the item on its website: "The costumes were extremely valuable. Each pearl shell used in the mask and apron might have to be purchased with a pig, and many hours of labour were needed to shape and stitch together the many thin rectangles that make up the apron."
The chief mourner was concealed by the elaborate costume.
"If you were living in the Society Islands in the late 1700s, and you saw someone wearing this costume coming in your direction, you'd know that (a) someone important had died and (b) you'd better run away or hide smartly."
The website continued: "When a chief died, the bereaved family would arrange for a group of mourners to grieve publicly. This costume is what the leading member of that group would be wearing. Other mourners in the group would be naked apart from a maro, a loincloth, and would daub themselves with soot, often with red and white decoration painted on top.
"The group's task was to go around the chief's territory, acting crazy with grief, and terrorising everybody in the process. The mourners warned of their advance with special shell clappers. They carried weapons and could be expected to use them. Woe betide you if you crossed the group's path and couldn't or didn't get away in time. You might get beaten up, even killed."
The ritual could last for several months.
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Te Papa believed its ahu parau is made up of pieces collected during Captain Cook's second voyage, when he travelled through the Pacific and stopped in New Zealand – between 1772 and 75.
The item is one of 24 reported damaged between March 2018 and May 2019.
Eight were reported during Michael Parekowhai's Detour, which had included many of his own works, plus notable pieces by other artists.
One explanation for damage was noted as: "Security footage shows a cleaner hitting the tree trunk while trying to turn the floor cleaning machine".
Another piece was damaged after a visitor sat on it for a photo.
Te Papa did not report the repair costs, which are the responsibility of its conservation team.
A Te Papa spokeswoman said "protecting collections is absolutely the core of what we do".
The museum was constantly trying to "strike a balance" between letting people get close to objects, while also ensuring the treasures remained safe.
"There are a range of strategies from putting things behind glass, having barriers and alarms, having signs and other design features in the galleries, or having protective glazes on paintings," she said.
"Our floor staff report on things that have been touched – on purpose or by accident – and we assess the risk make adjustments based on that.
"We have specialists on staff, called conservators, whose job it is to care for collection objects. They can sometimes repair damage but prevention is always better than cure."
Te Papa realised that touch was "an important sense".
"And we try to cater for it. For example, if we know people are going to want to touch a particular artwork, we might provide a sample of the material next to it for people to touch."
Most of the 24 damaged items highlighted by Te Papa are artworks.
The spokeswoman said given more than 700,000 people a year visited Te Papa's art gallery, Toi Art, it showed "most people are really careful and respectful".