A Christchurch shopper is urging people to check their bank statements after being overcharged five-fold

Eftpos company Windcave has admitted it's at fault for Christmas shoppers being overcharged on Saturday.

Simon Hunter says other shoppers need to double-check, after he was overcharged for goods worth one hundred and 35 dollars, at The Warehouse.

He says it would have been a miserable Christmas if the refund hadn't come back yesterday.

Windcave says wrong charges were made for some merchants processing the Windcave-BNZ link for an hour on Saturday afternoon.

The company says they're in the process of working with the bank to reverse the charges.