Banning motorists from Eden Quay may have a "detrimental impact" on businesses, the Dublin Chamber of Commerce has warned.
A submission was made this week to Dublin City Council (DCC) by the business chamber, outlining the consequences that imposing the ban may have.
In February, DCC announced that private cars are to be banned from travelling along the quays in Dublin. This will allow DCC to introduce more bus lanes to prepare for the new Luas Cross City.
In a report to the Transport Committee, council management said the Luas will be halting traffic movement on the Quays every 90 seconds and the changes are being made to limit congestion.
Graeme McQueen of Dublin Chamber of Commerce told the Herald this ban would be like "turning off a light switch and expecting everyone to find their way around in the dark".
"As a chamber for businesses we're always happy for change in the city centre, but we have got to be very careful imposing big measures like these," he said.
"We've been asking DCC how they can make sure that this is going to be beneficial, but we still don't know how people are going to get around once cars are blocked from using Eden Quay.
"This makes us very nervous. There's no guarantees that changes like this are ever going to work, but we still need some assurances."
Last month, motorists were barred from turning onto Eden Quay from O'Connell Bridge as part of the ongoing construction works. The permanent change will only allow public transport and cyclists to access the route.
Mr McQueen added that companies will be put off from investing in Dublin city centre if it introduces this measure.
"It may have a detrimental effect for existing businesses in the city centre, more people will surely choose to avoid travelling there," he said.
"It could also turn off potential companies from investing here due to poor manoeuvrability and logistical options, along with long and/or inconsistent commute times."
The Dublin Chamber also warned of a potential increase in congestion on the M50. As part of this controversial initiative, extra bus lanes may be introduced along Ormond Quay, Bachelors Walk and Eden Quay.
Eden Quay from O'Connell Street to Marlborough Street will be used only by public transport, taxis and cyclists.
The south quays will have an extra bus lane along Burgh Quay, Aston Quay and Wellington Quay. In addition, there will be a new bus lane on Winetavern Street at Christchurch for traffic coming onto the quays.
The plans coincide with the proposed Liffey cycle route, which could see all private traffic rerouted from the quays between James Joyce Bridge and Fr Mathew Bridge up to North King Street and North Brunswick Street and back down Queen Street or Church Street.
Joe Herron, head of the Irish Taxi Federation, told the Herald that he believes the vehicle ban will create chaos for Dublin's city centre.
"I think it's going to create terrible chaos," he said. "The whole idea of stopping private cars from travelling on the quays will contribute towards the death of trading for the city centre. 'There is no doubt that the city isn't as busy as it used to be. It's like DCC wants to turn the entire area into a public transport location only.
"The problem with this is that it won't suit many people who can't use public transport for going to work or shopping.
"The parking fees in town are also very high and it's making the various shopping centres around the capital seem much more attractive," he said.
In recent weeks, driving in Dublin city centre got significantly slower after authorities expanded the number of areas with a speed limit of 30kmh.
The new limit was applied to non-arterial roads in the Dolphin's Barn, Kilmainham and Smithfield areas from Friday following a vote by Dublin City councillors in December.
The measure will also be extended to residential zones in the wider Dublin area from May 31.