The bikes-in-boxes promotion is in the new Christmas catalogue from Halfords.
The promotion mentions a free safety check is available on all bikes, but does not highlight if this covers bikes built by anyone other than Halfords staff.
Mark Brown, ACT's sales and marketing manager, said:
"It would appear that the UK's leading cycle retailer has not considered the realities of purchasing, especially over theChristmas period. For many, I'm sure a boxed bike is easier to buy and wrap, and gives mum or dad an opportunity to make a short term saving by building it themselves without appreciating the tools and knowledge required to do so properly.
"Quality cycle retailers do not believe in offering a bicycle for sales unless it has been built and safety checked by a trained individual, and certainly do not make this an optional extra.
"The issue of bikes in boxes is a serious problem for both independent retailers and for consumers themselves. Key issues regarding safety and warranty are not being addressed by those retailers selling unassembled bikes in boxes."