The Driver and Vehicle Licensing Agency (DVLA), which monitors car tax, will automatically issue fines of £80 for drivers failing to renew their tax discs on time. Until now, a vehicle had to be spotted on the road unlicensed and unregistered for an offence to be committed.
However, motoring groups have criticised the move, saying it would unfairly penalise people who are in hospital or out of the country while unregistered drivers, who pose the greatest danger would escape undetected.
The DVLA says the new rule aims at clamping down on car crime and that it will not make any allowances for people who have simply forgotten to buy a tax disc.
The Association of Car Fleet Operators (ACFO) is warning fleets to ensure their policies and procedures meet the new requirement.
Director Stewart Whyte, who has been involved in meetings with the DVLA in the build-up to the introduction of the new system, said: 'Fleet operators who are registered keepers of vehicles must have in place a system that enables them to renew vehicle excise duty discs as soon as they fall due.
'Predictably, the fleet sector is not seen as a major problem area by the DVLA. But no fleet operator will want to find itself penalised because of a minor administrative slip-up.
'That is why all fleet operators need to ensure that their policies, procedures and disciplines allow them to raise cheques and re-license vehicles by the end of the month when the new tax disc is due. A failure to do so will now automatically trigger a fine.'
Whyte added: 'Fleet operators which lease or have outsourced licensing administration to a fleet management company should discuss with their service providers how they are going to be indemnified against a fixed penalty notice should there be a delay in administrative procedures.'