The value of retail sales fell by $25 million, or 0.5%, in July compared with the same month last year.
The total value of retail sales in July was $5.39 billion.
In the core industries, the biggest drop was in department stores where sales were down $7m.
Among the larger increases was a $7m rise in the amount spent on accommodation.
UBS senior economist Robin Clements says unemployment and tightened wages will continue to rein in people's spending, and he thinks a strong recovery is not likely before next year.
Retail sales rose 1.1% in June.
