Chief executive Richard Wyeth says the announcement will give certainty to their 400 farmer suppliers.
"There was some conjecture about payment and we've put that to bed," he told Dairy News.
Westland has been paying 10c above Fonterra's farm gate milk price for the past few seasons. The deal will now extend until the 2025-26 season.
Another milk processor, Synlait, faces the risk of farmer suppliers switching their supply to other processors like Westland and Fonterra.
Wyeth says they aren't actively advertising for suppliers.
"But i there are new suppliers interested in supplying Westland, our milk supply team will be happy to talk to them."
