China-controlled Mataura Valley Milk's production is under way with the first milk delivered to the company's $240 million nutrition plant at Gore today.
Founding director Ian "Inky" Tulloch, a Southland businessman and racing identity, said it was satisfying to see the plant open after eight years of hard work.
Tulloch said in a statement the project was already having a big impact on the district.
Mataura Valley's major shareholder is the state-owned China Animal Husbandry Group.
"It's a proud day for our team and everyone involved in developing what we believe will be the world's best nutrition business," plant general manager Bernard May said.