Price and product comparison site PriceSpy predicted almost a fifth (18 per cent) of products would be cheaper the day after Christmas.
Consumers would get an average saving of 13 per cent per item.
"Despite the popularity of Black Friday increasing by 20 per cent this year, our figures indicate Boxing Day appears to be more prevalent amongst price-savvy Kiwis," Lisa Matinvesi-Bassett, New Zealand country manager for PriceSpy, said.
"If shopping is to follow a similar pattern to that of last year, the percentage of consumers searching for products on Boxing Day was at an all-time high, increasing 321 per cent compared to the Tuesday before."
Kiwis spent $69.7 million at non-food retail shops on Black Friday 2018, surpassing the $68m spent on Boxing Day last year, according to figures from Paymark.
But both days trailed that of Christmas Eve last year when sales surpassed $82m.
Paymark also added that Boxing Day was likely to surpass Black Friday this year.
Figures from Kiwi Property showed more than 280,000 people visited one of its six shopping centres on Boxing Day 2017.
Kiwi Property owns and manages Sylvia Park and LynnMall in Auckland, Centre Place and The Base in Hamilton (jointly with Tainui Group Holdings), The Plaza in Palmerston North and Northlands in Christchurch.
But Matinvesi-Bassett said while their data suggests Boxing Day appears to be the most popular day among New Zealanders, the overall percentage of products discounted seems to be bigger on Black Friday, with 23 per cent of products being discounted compared with 18 per cent on Boxing Day 2017.
"For consumers, the trick will be sitting back and observing how prices fluctuate. If there's a specific item they're hoping to buy, we recommend they set up a price alert using the PriceSpy app and wait to be notified when the price drops.
"Don't be lulled into the false economy that prices are actually cheaper on Boxing Day than at other times during December or January," Matinvesi-Bassett said.
Based on historical price data, PriceSpy predicts the cheapest Boxing Day products will come from the shopping categories of televisions, headphones and mobile phones.
"For those looking to buy a new television, our research indicates Boxing Day is the best time of year to buy one," Matinvesi-Bassett said.
"For example, last year 65 per cent of products listed under the shopping category of 'televisions' received a Boxing Day discount and the average saving offered was 22 per cent."