CENTRAL banks loaded up on the Australian dollar in the first quarter, just before the currency began a steep descent that would see it touch its lowest level in nearly three years, data from the International Monetary Fund shows.

The US-dollar value of central bank reserves in the Australian currency jumped to $US98.7 billion in the first quarter from $US89.7bn in the fourth quarter, the data showed.

The Australian dollar is down about 12 per cent from the beginning of the second quarter, trading at US91.66c, its lowest level since September 2010.

Central banks also increased their share in the Canadian dollar, boosting their holdings from just above $US90bn to $US94.9bn. The Canadian currency, known as the loonie, saw a pullback of more than 3 per cent in the second quarter.

It was the first time the IMF included data on the Australian and Canadian dollars in its Currency Composition of Official Foreign Exchange Reserves, a reflection of the currencies' growing popularity among reserve managers. Previously, the two currencies had been consigned to the "others" category.