"Retail volumes were much firmer than expected in the June quarter following a slightly soft March quarter," Snowden said.
"Increased spending was seen in the majority of classes, although accommodation took a small step back, a surprise given the strength of tourism," he said.
"Spending in housing-related categories was firm, with consumers adding value to their already appreciating homes and furnishing them."
Motor-vehicle and parts retailing rose 2.6 per cent, pharmaceutical and other store-based retailing increased 5.2 per cent and food and beverage services jumped 3.3 per cent.
The biggest declines were in fuel retailing, which dropped one per cent, and recreational goods, which dropped 3.3 per cent.
On an annual basis, the quarterly value of actual retail sales rose 5.5 per cent to $19.9 billion, while volume rose 6 per cent.
Westpac's economics team attributed part of the strength in spending to the continued softness in prices, allowing households' pay packets to stretch further. It estimated that retail prices were down 0.2 per cent over the quarter, and 0.5 per cent over the year.
Spending has also been boosted by low interest rates, strong population growth, and high tourist numbers.