Dozens of clothing makers in Vietnam have had their US quotas withdrawn or reduced as part of a government crackdown on companies which abuse the system.

Trade officials on Wednesday said 51 companies have lost their quotas or had them slashed after they were found to have made lied when they applied for the lucrative permits.

Investigators found several of the offenders claimed they had factories when they actually had none while the others were found to have overstated their production capabilities.