Synlait Milk said it had started a process with staff to reduce the company's headcount by about 15 per cent - or 150 jobs - to achieve savings of $10 to $12 million.
Chief executive John Penno said Synlait, whose previous chief executive Leon Clement left in April, had been through a lot of change over the last 12 months.
"This means some areas are now over-resourced, and some areas are under-resourced," he said.
"We need to review and reset the structure of our business to match our current goals to be successful," he said.