The factory will produce infant milk formula and other dairy ingredients.
Happy Valley Nutrition chief executive Greg Wood says the OIO approval was a key milestone for the company.
“We now have in place a much stronger foundation to advance the project to the next stage,” he said.
“We look forward to updating shareholders on our progress more regularly now we have this consent locked down.”
The OIO approval allows Happy Valley to progress discussions with financiers, advance early site works, tender the main contract for the dryer process plant and progress securing conditional customer supply agreements.
The company had previously obtained resource consents for land use, water take and to discharge air, stormwater and wastewater for the factory.
The company has also made four non-binding heads of agreements in place for the supply of product once the facility is operational.