Orr, the newly-minted Reserve Bank Governor, said the changeover to the new notes is progressing slower than expected.
"Six is being destroyed at a slower rate than perhaps what we thought so seven is being circulated at a slower rate," he said. "I think a lot of currency goes out and stays out."
The central bank has just completed a research programme looking at the wider currency cycle and has found that while the majority of New Zealand's cash stays in the country, about a third is held outside of the country.
"A lot of the cash that exists doesn't necessarily come back so it's being used as a store of wealth and a means of exchange in other countries," he said. While this was a sign of confidence in our currency, it left open the question of what it was being used for, he said.
While the Series 6 is easier to counterfeit than Series 7, that doesn't mean it is actually easy, Orr said. Series 6 was state-of-the-art, the first of New Zealand's notes to be printed on polymer, improving durability and enabling windows to be included as an enhanced security feature.
Part of the Reserve Bank's research was looking at how to forecast future demand for cash. Despite the increased use of electronic payments, the amount of physical currency in circulation continues to grow every year as the economy expands and people still like to hold something tactile, particularly following events like earthquakes.
"The death of the currency is much exaggerated at the moment, and likewise the life of a lot of these cryptocurrencies," Orr said.
Cryptocurrency doesn't tick the boxes requiring it to be a means of exchange, a store of value, and a unit of account so while the Reserve Bank is open-minded about the future, it wouldn't rush to be a leader in adopting a central bank cryptocurrency, he said.