Business owners could face "financial ruin" if any future development of Murray Bridge's main street is not done right.
A dozen traders have written to the city's council to urge it not to do to Bridge Street what it did to Sixth Street last year.
"Bridge Street traders do not want full-scale road and footpath reconstruction," they said in a joint letter.
"A steam clean of the red pavers would bring about an immediate improvement without disruption to their businesses and customers.
"A welcome improvement would be continuing the Sixth Street appeal that the bins and seating provide ... and providing a safe, people-friendly environment."
Bridge Street traders do not want full-scale road and footpath reconstruction.
The fact that the Sixth Street works dragged on into November and December, when businesses relied on getting enough trade to make it through the lean winter months, was a particular worry.
The traders – including newsagent Adrian Pergallini, chocolatier Ian Pithers, shoe seller John Beauchamp and Sportspower's Richard and Sherryn Crane – said some Sixth Street businesses faced financial ruin because customers irritated by the inconvenience would not return.
They were also unhappy with the council's approach to consultation: "a newsletter does not replace a genuine conversation".
At a council meeting on Monday night, Councillor Tyson Matthews said he did not think the community wanted major changes on Bridge Street.
"Let's not over-complicate it," he said.
"People just want to maintain the functionality of this street.
"It's encouraged me more to think about some smaller things we can do that are less monetarily orientated and more about vibrancy."
Councillors agreed to keep the traders' concerns in mind if they revisited the idea of upgrading Bridge Street.
A majority of people who voted in a Standard poll in March wanted to keep two lanes of traffic each way.