At that time, the main currency for arbitrage transaction was yen, because the interest rate was low for yen then, and many objects of arbitrage transaction were AUD and NZD.
The currency used for the carry trade at that time was mainly the Yen because of its low interest rate, and the objects for many carry trades were AUD and NZD.
The main currency in the Carry Trade is Yen, because at that time the interest rate of Yen was very low. And many operations of Carry Trade were marked by AUD and NZD.