Minkisi (the plural of nkisi) are sculptural statues - or, more often, simple containers such as bottles or shells - into which a spirit has been lured to take up residence.
These figures, bristling with an interesting assortment of nails and metal, are not the aggressive pieces perceived by Westerners, Bovey says.
"A minkisi primary function is to protect."
When Bovey first acquired the pieces, he became obsessed about what shaped them: "Not only the aesthetic codes but the beliefs."
Through ritual, minkisi acted as a kind of interface between the world of the living and the world of spirits. Villagers consulted them to swear oaths and forge pacts and to gain protection from illness and other misfortunes.
The nails in some of the pieces represent a pact or a request, driven in with appropriate ceremony by the nganga (priest) whose wealth and reputation was linked to that of his nkisi - this was their unspoken word of honour.
The sculptural forms are fascinating and each is art in its own right.
And while at first glance the pieces could look menacing, closer examination and understanding of how each piece has been constructed gives insight to the use of the materials, and why. Most minkisi statues wear a mirror on the belly behind which "magic" materials are sealed in a cavity. By consulting the mirror, the nganga was able to see into the past and the present and detect malevolent forces menacing his client.
Chimpanzee skulls, goats' teeth, monkey hair and a civet skin are some of the materials used.
Bovey says Westerners define a minkisi by what they see. The baKongo (the tribal people) describe what it "does".
Inspired by his growing collection, Bovey visited museums; the Quai Branly and the Musee Dapper in Paris, and the Musee Barbier-Mueller in Geneva.
And he began to read.
"Instructing one's self about African art and belief can't be done just by collecting facts. There is a dimension you have to confront, even if you can't adhere to the faith behind it."
There has to be a willing suspension of disbelief.
Bovey said he was scared the first time he went to Africa, but he wanted to go alone. His first trip was to Tanzania, one of Africa's safer countries. He found stunning landscapes, but there were no forests, no wood and little sculpture.
When he returned to France, Bovey discovered in further reading that the major sculptural traditions came from the equatorial jungle zones, and these were almost all ex-French or Belgian colonies.
His next trips were to Cameroon and on to Gabon and more of a challenge than Tanzania. But the naturalised French was not a problem to the now-fluent French-speaking Bovey.
"I loved the edginess of west Africa, living on my wits and far from other whites." But, he says, he was protected by his "huge innocence".
He found Africans to be more informed about Westerners; they watch television every night. Africans live in a world with more dimensions than his Pakeha one, he says. "Africans, by nature, are extremely secretive, and I soon learned that there was a time for chat and questions, and a time for silence."
Bovey says we all have cultural codes that affect our way of looking.
"When we contemplate objects from cultures other than our own, we have to unlearn these codes if we hope to understand them."
Bringing his collection home was a huge undertaking. It had to be packed in crates - some of the pieces are very heavy, and all required careful handling.
It had to be fumigated in Europe and MAF in New Zealand required it to be fumigated when it landed here. He also required a CITES permit (Convention on International Trade in Endangered Species) because of some of the materials that were used.