They produced a spend of $40.3million in May, a 4.4 per cent lift on the $38.6million spent in May 2013.
He said nationwide the figures pointed to a strong and consistent month of trading, annual growth in the volume of transactions processed the fastest since 2008. Kiwis swiped or tapped their cards just under 90 million times in May - and the surge was especially notable during the first seven days when spending was up 9.1 per cent across the country, compared to the corresponding week of trading in 2013.
He said stronger trading throughout May could be explained by several factors, one of those being the fact there were five Saturdays this year, but only four last year.
"With Saturday being the day of the week that typically results in the highest volume of transactions processed through our network, this will have impacted the data ..."
Trends associated with credit card spending outstripping debit cards had continued last month.
"This is something we can expect to see on an ongoing basis, as more and more contactless cards come into the market and merchants enable their terminals to accept this payments method," Mr Spicer said.
Trading was strong in hospitality, with a 14 per cent rise nationally year on year. Food and liquor stores also recorded a lift (12.3 per cent).
Spending was modest among department stores, appliance retailers and clothing shops compared to 2013, and continued to decline within the book, stationery and video sector.