A child safety lobby group is warning parents that badly assembled bicycles can create a hazard for children.
A spokesperson for Safekids New Zealand, Ann Weaver, says DIY-assembly products only meet safety standards if they are assembled correctly.
She says police running cycling events at schools have often found children's bicycles unsafe because of the way they have been put together.
That can mean bolts are not tight enough, parts are on back to front, or a piece critical to safety has been missed out.