Fonterra will lend the money until April 30 next year.
RD1 is half owned by the Australian Wheat Board through its Landmark Rural Holdings operation which bought a stake in 2006 for about $40m.
Fonterra said the loans will will help farmers struggling with the 13 percent reduction of this season's forecast payout from $5.20/kg of milksolids to $4.55/kg.
"It's a tough time for our farmers," said Fonterra's director for milk supply Barry Harris, who is also a director of RD1.
The lending would open up another option to cut costs and manage cashflows and provide some flexibility for farmers needing essential supplies to keep their farms running.
RD1 will fund the interest costs of the loan.
