Tru-Test has bought Dairy Technology Services, a milk storage and refrigeration company.
The agri-tech firm took over ownership of DTS from NDA, a stainless steel engineering company, late last week.
DTS has 80 employees in both Taranaki and Hamilton.
The deal follows Tru-Test's purchase of Radian Technologies and its dairy management system, MilkHub, in December.
Tru-Test chief executive Greg Muir said the move is about growing the company's presence in the dairy industry. He would not reveal the value of the acquisition.
NDA said the deal was a logical move and would allow it to focus on its engineering activities in New Zealand, Australia and North America.