Retail NZ chief executive Mark Johnston said spending on watches and jewellery, health and beauty, books, video, music and photographic sectors was strongest.
"These are the sorts of sectors I'd expect people to be spending in as they buy their gifts for Christmas," he said.
Spending on accommodation and hospitality was up 8 per cent year-on-year and up at supermarkets and other food stores by 7.6 per cent. But spending on clothing and footwear was described as weak.
"Retailers are facing real challenges in a competitive marketplace, with strong competition from overseas retailers," Mr Johnston said.
"But it's too late now to buy goods from overseas for Christmas, and we're expecting a last minute spend-up as Kiwis rush to finish their shopping tomorrow.
"Christmas Eve is usually the biggest shopping day of the year, and we expect this year to be no exception."
Electronics retailer Dick Smith is also hoping to take advantage of the Christmas Eve madness, bringing its annual Boxing Day sale forward to 6pm today and running it for five days.
Chief executive Nick Abboud said online sales were expected to more than double this year, and "big ticket and limited volume items such as the latest TVs, laptops and notebooks are expected to fly off the shelves".
Warehouse chief executive Simon Turner said 8pm on Christmas Day last year was thewarehouse.co.nz's busiest time of year, "showing just how excited New Zealanders are to jump online ... and take advantage of early Boxing Day bargains".
Shopping tips
•Ask for an exchange card.
•Don't be fooled into buying extended warranties.
•Check the expiry date on gift cards.
•If you receive a gift card, use it before you lose it.
•If an online purchase doesn't arrive, ask your bank for a charge-back.
•Check receipts and bank statements.
•If you buy something then regret it, a retailer has no obligation to take it back.
Source: Consumer NZ