The Hokitika-based subsidiary of China's Yili, Westland Milk, said it had bought Waikato dairy food manufacturer Canary Foods for an undisclosed sum.
Canary Foods, which was established in 2001, exports 75 per cent of the dairy products it manufactures.
The company produces "reworked" premium butter and cheese-based products such as butter sheets and medallions for use in the retail and food service sectors, including supermarkets, airlines, restaurants, and bakeries.
Westland chief executive Richard Wyeth said Canary acquisition was a "fantastic fit".
"After our $40 million investment in doubling our consumer butter manufacturing capacity at Hokitika, this extends our long-term commitment to add value to Westland's butter portfolio by playing a greater role in the expanding global consumer butter and spread market," he said.