The chain starts its late-night shopping hours this week.
"But on Christmas Eve, we're only open nine to six - Santa's got to get back to get ready," said Ms McGhie.
There hadn't been any incidents of Christmas shopping stress rage yet, but Ms McGhie said those sorts of incidents tended to happen closer to December 25.
"We brought in extra customer services a little bit earlier this year ... that just helps take the pressure off and so far, so good - people are being kind to one another. Hopefully it stays that way."
Paymark figures show spending between December 6 and 12 was up 4.1 per cent on the same dates last year, a higher than average annual growth rate.
During that period, $1 billion passed through its network.
The busiest shopping day so far this month was Friday, December 7, with more than $164 million going through the tills.
Spending growth was high at hardware and building supplies outlets, appliance stores and floor covering and furniture retailers - all outlets tied to the housing market.
Stress-free presents
Gift vouchers - A great solution to the stress of trying to pick the perfect gift. But keep track of the expiry date - once it's passed the trader has no obligation to honour the voucher.
Gift cards - The same but in a credit card form. May cost extra in fees. Also, the expiry date may not be on the card, so ask in store.
Returns and exchanges - Arrange these beforehand with the retailer. Generally you'll need a proof of purchase, such as a receipt, and the item should be unused and packaging sealed.
The gift of safety - Check kids' stuff is covered by safety standards and check the voltage of electronics - they must be 230 volts and 50 hertz to be safe.
Source: Consumer NZ