Birmingham's biggest business organisation will not back congestion charging without significant improvement to public transport being put in place first.
The Chamber of Commerce said it would be unfair on businesses and retailers to impose a levy on vehicles entering the city centre unless travel by bus, train and tram was made easier.
Chamber spokesman John Lamb said: "We are told that retail in the city centre is booming. But in the long term we have always said that any form of congestion charging has got to be coupled with improvement in the public transport infrastructure, both rail and road.
"Until that happens, congestion charging isn't a goer."
City centre retailers risked being "left out in the cold" by motorists who would use outof-town shopping centres with free parking rather than pay to drive into Birmingham, Mr Lamb warned.
The Chamber is backing a report by the Forum of Private Business, which warns that congestion charging could turn out to be a costly tax on business owners and employees.
The FPB report adds: "We have seen by the hikes in London's congestion charge that this is just another way of raising revenue. Smaller businesses need the reassurance that these greener taxes are being introduced with an ecological goal not a financial one. Charging for entering the city and town centres will be costly for those businesses already struggling to compete with the advantages of the big retail parks.
"We have seen the consequences for smaller businesses in London with footfall and profitability down and many firms relocating to outside the congestion charge zone."
FPB chief executive Nick Goulding said: "Everyone agrees that cutting congestion is in the interest of the environment and the economy, but road pricing isn't a definitive solution.
"Traffic reduction will go hand in hand with genuine alternatives such as improved public transport, whilst long term growth in the economy will be severely hampered if smaller firms are taxed out of existence by revenue-generating exercises that are dressed up as green taxes."
Seven West Midlands local authorities, including Birmingham, Coventry and the Black Country boroughs, have been given more than £3 million by the Government to investigate road pricing.
An initial report published in September - Gridlock or Growth - suggested a £5 daily charge to drive into Birmingham city centre.
If chosen to pilot congestion charging schemes, the councils would be given a share of the £1 billion Transport Innovation Fund, which is designed to deliver public transport improvements.