"To supply bicycles that do not comply with safety standards is something I regard as serious," Sharp said.
He said Container Door was co-operative with the Commerce Commission and had recalled the bikes.
The Herald understands 10 of the 15 bikes were returned.
Container Door sought a discharge without conviction but Judge Sharp declined to enter it, saying the consequences of a conviction were not out of all proportion to the gravity of the offending.
Commerce Commission general manager of competition and consumer, Antonia Horrocks, said "Container Door was supplying bikes that put riders, pedestrians and road users at risk of serious harm because there was no front brake".
This impeded a rider's ability to stop and control their bike.
"It is important for traders to know their legal obligations and to operate compliance programmes to ensure they comply with the law," she said.
More to come.