Most retailers that use computerised check-out and barcoding systems are members of GS1 New Zealand. Their code of practice states that:
- prices should be displayed so they can be read and linked with the product easily
- the retailer can’t charge more than the displayed price.
A trader or retailer who is not a member of GS1 New Zealand doesn't have to advertise or display their prices.
Usually, if a price is advertised or displayed incorrectly at a substantially lower price, the trader doesn’t have to sell at that price. But if they often advertise products at the wrong price or for a long time, they may be breaking the Fair Trading Act by misleading you about the true price.
If you have been undercharged, the trader can’t ask you to pay the extra amount after the sale is completed unless you knew:
- there was a genuine mistake about the price, and
- it was much less than it should have been.
Advertised prices must be genuine, and there must not be extra costs you weren't told about.