The plant, officially opened by Jaala Pulford, the Australian Minister for Agriculture and Regional Development, will produce Woolworths Select fresh milk for stores in the Australian state of Victoria for the next decade.
Fonterra Australia landed the 10 year contract with Woolworths in Victoria in April 2014 - replacing its Australian rival Lion Dairy.
It said then it would spend more than AU$30m to build a fresh milk plant at Cobden.
Around 115,000 bottles of fresh milk will leave the plant each day for Woolworths stores across Victoria.
"Last year we approached Woolworths with a plan to build a state-of-the-art facility that would bring fresh innovation to fresh milk," Judith Swales, managing director, Fonterra Australia, said at the opening.
"Woolworths shared our vision, and together we formed a ten-year partnership that would help us bring it to fruition."
"With the security of that ten year partnership Fonterra made a multi-million dollar investment into this amazing facility," Swales added.
The plant, where 50 new jobs have been created, is a "concrete example" of the benefits of long-term milk contracts, Woolworths said.
“Woolworths is delighted that as a result of this contract Fonterra has the confidence to make a major investment in Victoria which benefits not just the industry but also our customers,” said Ewan Shearer, merchandise manager for chilled products, Woolworths.
“The new plant will deliver customer benefits like packaging innovations including induction seals that ultimately mean a better product on the supermarket shelf and in the fridge at home," Shearer added.