Arla Foods, a Danish-Swedish co-operative, will begin selling skim milk powder on Fonterra's global dairy trade auctions next year.
Fonterra says the addition means that the auctions will be selling product from all the major dairy exporting regions: Europe, America, Australia, and New Zealand.
It also means the auction will have three sellers of skim milk powder, which Fonterra says will further deepen liquidity for auction participants.
Arla will begin selling from 3 April.
It has production facilities in 13 countries and sales offices in a further 20, and more than 16,000 employees.