Possibly Oxalis magellanica, which is native to Aotearoa and South America (magellenica as in Straits of Magellan), but while NZ has some native Oxalis species, it has considerably more that aren't. Including Oxalis tuberosa, a staple crop in the Andes and highly popular in New Zealand where they're called yams.
There are some 550 species of Oxalis worldwide, most of them in tropical Brazil, Mexico, and South Africa. The common name wood sorrels refers to their acidic taste (from Oxalic acid) reminiscent of the true sorrel (Rumex acetosa), which is not closely related. Other common names include as false shamrocks, and sourgrasses.
Hāwera, Taranaki, New Zealand