New figures show as many as 40% of motorcyclists are riding around on untaxed bikes.
The DVLA's ability to enforce road tax could become a "laughing stock" if they fail to clamp down on unpaid motorbike tax as new figures suggest as many as four out of ten motorbike users avoid paying it.
The Commons Accounts Committee found evasion rates had risen 5% during 2006/7. This was up 3.6% from 2005/6 figures and is estimated to be costing taxpayers up to £214 million.
Committee chairman Edward Leigh said: "Motorists and motorcyclists who refuse to pay road tax are stealing from law-abiding taxpayers and unlicensed vehicles are often associated with other forms of crime".
"Motorcyclists are particularly liable to evade road tax. Nearly 40% of motorcycles are now unlicensed."
"If the DVLA's motorcycle enforcement regime is not to be a complete laughing stock, then the agency and the department must make the most of new powers to enforce VED on public roads."However, The Motorcycle Industry Association claimed the figures regarding avoidance of Vehicle Excise Duty (VED) have been exaggerated.
The association said: "As a tool for informing policy makers about targeting resources to reduce VED evasion in respect of motorcycles, the current survey appears deeply flawed."
"There is reason to believe the methods employed may grossly over-estimate both the size of evading motorcycle stock and the consequent revenue loss it represents."
However accurate the figures are, The Department of Transport is currently working with the DVLA and the police to bring new measures to combat biker tax evasion, bringing in new technology and legislative measures.
"New automatic number plate recognition cameras, capable of detecting motorcycle number plates, are being used in targeted enforcement operations at motorcycle events," a spokesman said "And, from September, new legislation will allow the police, DVLA and local authorities to take action against unlicensed vehicles even if they are not parked on public roads."
