Half the door supervisors quizzed in a spot check in Glasgow are still not complying with Security Industry Authority (SIA) licensing requirements, three months after they were introduced.
Since November 2007 it has been illegal to work as a door supervisor in Scotland without an SIA licence.
However spot checks carried out by the SIA last week in Glasgow city centre found that half of the 18 staff checked did not hold a licence.
Previous checks carried out over Christmas by the SIA on 76 door staff across Scotland found that 37 per cent did not hold a licence.
Illegal door-staff and licensees who fail to ensure that their staff have the correct paperwork face a maximum penalty of six months imprisonment or a fine of up to £5,000.
Jennifer Pattinson, SIA head of investigation, said: "Door supervisors, working without an SIA licence, and those deploying them, are committing an offence. Licensees risk having their premises closed. We urge other licensees to check that their security suppliers operate within the law."
The SIA may take legal action against those caught out in last week's checks.
Patrick Browne, chief executive of the Scottish Beer and Pub Association, said: "These figures will come as a concern to the licensed trade in Scotland, given that they appear to suggest that at least some of the problems which plagued the introduction of the SIA in England and Wales appear to have now rolled into Scotland."