Bookseller Borders has been given a sharp prod by the Commerce Commission.

It follows ads before Christmas which stated customers would receive $20 in vouchers for every $75 they spent. However small print that most people did not notice said customers could only redeem one $10 voucher in January and a second $10 voucher in February.

The Commission says that materially changes the large headline offer and makes it misleading. As a result Borders has now agreed to accept a $20 voucher for a single purchase.