Project leaders expect the expansion to create a further 100 jobs as it continues to meet the needs of 70 different markets around the world - just from the Clandeboye site alone.
Shareholders would see the benefits of the expansion in production of what was a high-return product, Fonterra operations readiness lead Chris Turner said.
And ultimately, the "benefits would flow right through the community", he said.
The build was expected to be completed next year. The plant would be ready for testing in May next year and start commercial production later in the year, Mr Turner said.
"The shareholder-owned business is creating a legacy in the region."
Demand for mozzarella was greater than the existing plant's processing capabilities could meet and Fonterra's latest project would fill a gap in the market.
"[It is] investing in milk processes that have high returns," Mr Turner said.
The mozzarella plant, construction of which started in October last year, would be 14m tall and targeted milestones were being met so far.
The company had received more than 400 applications from people who wanted to work at the new plant.
A total of 70 applications came from current employees who either wanted a change or wanted to advance their careers.
Fonterra also hosted a careers event last weekend, potentially adding to this number.
Aoraki Development chief executive Nigel Davenport said the potential "trickledown" benefits to the wider community from the mozzarella plant were great.
"It's more like a waterfall in some respects," he said.
The development would not only offer employment opportunities but had the potential to attract entire families to the area.
"It's exciting times," Mr Davenport said.
Fonterra Clandeboye
• Fleet of 78 tankers
• Makes enough product to fill 70 containers per day
• Can process up to 12.4 million litres of milk each day from more than 895 local farmers
• Two milk powder plants
• Two cheese plants
• Three protein plants
• Two cream product plants
• Sends products to more than 70 markets globally
