The owner of 15 Bike Barn stores is accused of advertising "half price" and "clearance" bikes which weren't discounted.
The Commerce Commission says it has filed 16 Fair Trading Act charges against Bike Retail Group and associated company Bikes International over alleged misrepresentations in 25 marketing campaigns between July 2013 and June 2015.
Bike Retail Group owns 15 of the country's about 20 Bike Barn stores, the commission said today.
The rest are owned by independent franchisees.
The commission alleges that Bike Barn's marketing campaigns were likely to mislead consumers about the savings available and that there was only a limited opportunity to get bikes at certain prices.