Porsche Cars GB has written to the London mayor, Ken Livingstone, to challenge the new charging structure for the congestion charge, which puts most Porsche cars into the G charging band – costing £25 per day.
Porsche drivers currently pay £8 per day, reduced to 80p if they are resident in London.
Andy Goss, managing director of Porsche Cars GB, said: "A massive congestion charge increase is quite simply unjust.
"Thousands of car owners driving a huge range of cars will be hit by a disproportionate tax which is clear will have a very limited effect on CO2 emissions."
But Blake Ludwig, campaigns director for the Alliance Against Urban 4x4s, says: "We know from the enormous amount of support for our campaign, and from our own surveys, that charging the most polluting cars a higher congestion charge is already very popular with the public.
"The new C Charge follows the polluter-pays principle. Why should ordinary Londoners who are making efforts to reduce their carbon footprint have to, in fact, subsidize those who choose to pollute more?"
From February 4th, lorries over 12 tonnes, with buses, coaches, vans and minibuses all being included in stages, became liable for their CO2 emissions under the LEZ – low emission zone – scheme, as well as paying for their congestion charges.