Last year the Mayor instructed Transport for London to investigate the feasibility of introducing the (ULEZ) which would require vehicles entering it to emit zero or low emissions or face a daily fine.
TfL has yet to announce when the new scheme, which is designed to improve the capitals air quality, would come into operation.
Assembly Member Andrew Boff says drivers risked being fined twice if the ULEZ and Congestion Charge operated at the same time and covered the same areas.
He said: “I have long believed that the Congestion Charge is a tax on the motorist, and that it has failed to really have the impact that was originally intended.
“It makes no sense to continue with it if the Ultra Low Emission zone goes ahead as planned. I would strongly urge the Mayor to consider scrapping the charge altogether and lighten the burden on London’s hard pressed drivers”.