Rudlin said she crunched margins as much as possible, but a lot of the bottles sold at the store appealed to collectors and drinkers looking for rarer "more interesting" labels.
The Whisky Shop has more than 500 bottles, some as expensive as $10,000, and is targeted to a more niche market. Rudlin said price fluctuates due to availability and currency and the deal a retailer can cut.
The Whisky Shop also sells to bars around Auckland and imports about 65 to 70 per cent of its bottles.
The Mill general manager Simon Templeton said there were many factors driving the price of whisky down, apart from the dollar. Asia was awash with whisky after bulk ordering during the global financial crisis.
"Generally we buy our whisky from overseas, so not from New Zealand distributors. We parallel import most of our whiskies. At the moment, especially with single malt, there has been a worldwide oversupply.
"The reason for this is, when the GFC hit, it seriously hurt the volume [being bought] compared to the amount suppliers had produced.
"People started to cut back. Just as people did in other categories, they started to say okay, we won't buy premier products. That created a worldwide oversupply. "Because we trade globally, we have been able to source our single malts from Asia, where there is a huge glut."
Templeton said retailers were taking advantage of the growth potential within the category as more 35-50 year olds were starting to drink the spirit. "Anecdotally, people don't just want to drink bourbon and Coke, vodka and Red Bull, people are looking for an experience and single malt is all about quality over quantity."