NZX says more than 20,000 lots have been traded on its Dairy Futures market.
The market, which allows buyers and sellers to lock in milk prices for delivery at a later date, got off to a slow start when it was launched in October 2010.
It took a year for the first 10,000 lots to be traded, whereas the second 10,000 lots took four months.
March recorded the largest volume day and the largest volume week in the history of the futures market.
Average daily volume is now over 200 lots per day.
NZX head of derivatives Kathryn Jaggard says there is increasing activity in the market from customers in Asia, who are hedging dairy purchases, and she expects that activity to increase.