Christmas Eve was possibly busier than normal because it fell on a Thursday, he said.
"It meant people got an extra paycheck which helps. In saying that, Kiwis aren't too adverse to putting things on their credit cards and people traditionally leave it to the last minute anyway."
Boxing Day was also "huge", he said. "I was one of the silly ones who thought I'd be able to get a carpark. It was mad."
Mr Walsh expected retailers to remain busy this month.
"We're just on the crest of the wave; it'll keep going. Tourists are keeping on coming which is great for retailers."
Rotorua Central Mall spokesman Gary Herbert said the surge in spending seemed to be because the Christmas period lasted longer.
"To be fair, I think it was up a lot longer this year. About six weeks out it started to build up as opposed to two or three weeks out like previous years."
He said it was a combination of tourists and locals spending.
Co-owner of Atticus Finch on Eat Streat, Kay Thompson, said more and more people had been coming to Eat Streat and business was good.
"We are up a lot at the moment and last month, probably about 15 to 20 per cent."
Nationwide, Kiwis spent an extra $397 million in December compared with last year. The growth for the entire country was up almost 8 per cent to $5.493 billion.
Paymark suggested several factors were behind the overall increase, including the Reserve Bank cutting the OCR to 2.5 per cent per annum in early December. This flowed on to lower mortgage rates, as well as continued GDP growth. And lower petrol prices were offset by strong accommodation figures as New Zealand experiences record tourist numbers.
The number of transactions across the country was also up year-on-year, with 8.2 per cent more transactions - 106.05 million - conducted on the Paymark network in December.
Additional reporting
Kyra Dawson
