"In the end, the economics of basing a plant in Timaru, coupled with a skilled stable workforce, meant that it was the best option," Mr Matthews said in a statement.
Commissioning of the plant was also bringing jobs back onshore.
"Currently, 80 per cent of our export production has secondary processing in Indonesia.
"However, bringing jobs back onshore is not without its challenges. The challenge for us as a company is to upskill our workforce to meet, and ideally exceed, the exacting standards that we currently obtain from our world-class processor, BMI, in Indonesia," he said.
Commissioning the plant was a "vote of confidence" in a New Zealand workforce. It was designed to process, at full capacity, 3500 metric tonnes of harvested fish a year.
The company, which is more than halfway through a $20 million expansion, recently became the first aquaculture facility in Australasia to receive the Global Aquaculture Alliance's best aquaculture practice certification for sustainable farming.
Mt Cook Alpine Salmon chairman Jim Bolger, described as not only a tremendous achievement for the company, but also a "significant moment" for New Zealand aquaculture in general.
The Global Aquaculture Alliance is an international organisation dedicated to advancing environmentally and socially responsible aquaculture and a safe supply of seafood to meet growing world food needs.
Obtaining certification would open up "significant" new markets for the company, Mr Bolger, who is also the chairman of the international board of the World Agricultural Forum, said.
To achieve certification, independent auditors from the Ireland-based Global Trust travelled to the Mackenzie Basin to audit the procedures, practices and operating manuals of the company's farming operations.
