Proposals announced by Shropshire Council mean Bridgnorth's High Street will be closed every week to allow for easier social distancing while the market takes place.
But Steve Robbins, chairman of the town's chamber of commerce, said shop owners he had spoken to were "fuming" and "concerned" about the closure on the busiest trading day of the week.
It comes after a previous Shropshire Council plan to keep shoppers safe which included the closure of the high street was axed.
Mr Robbins said: "While the chamber, town council and other interested parties were invited to a site visit on May 20 by Shropshire Council to agree measures to be taken to make the town centre safe when shops reopened, all of the agreed measures have been completely ignored.
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"This matter will have a devastating impact on traders in the town who are already struggling to survive having been unable to open for so long.
"Many rely on shoppers being able to access the high street to load goods purchased, and are concerned they will lose trade if this cannot happen. It will impact on disabled people who will not be able to park in the high street and bus passengers will have to walk into the centre."
The latest decision to close the high street comes after senior Shropshire Council officers visited the town and saw a lack of space for pedestrians while the market was taking place.
Steve Davenport, cabinet member for highways and transport, said: “It is likely that some stall holders will be required either to move away from the pavements, perhaps even turn their stalls around so that customers might approach market stalls from the centre of the closed High Street. It is likely that a one size fits all approach will not be possible.
“The likely changes will need the full cooperation of all market traders if we are to implement a plan that can satisfy the government guidance. These steps are being taken to allow the market to continue to trade and in a Covid-19 secure manner.
“The overriding concern at this time is public health. However, we are mindful of the benefits of doing what we reasonably can to manage the situation that is reasonable for all.”
Mr Robbins added: "Locally, shop owners have worked hard to ensure they comply with the requirements for safe shopping. Screens have been erected, tape has been used to mark out social distancing, market stalls have moved 1m away from the pavement, a one-way system has been organised under the Town Hall for pedestrians and one shop has even put up a traffic light to stop too many from entering.
"To be suddenly hit with the proposed closure of the High Street to traffic on the busiest trading day of the week is heartbreaking and a real kick in the teeth from Shropshire Council."
Bridgnorth Chamber of Commerce has launched its Safe to Shop campaign this week, with supplies of face masks being put in a number of shops for customers to use if needed.
Any trader who would like to comment on the closure can contact the town council at email@example.com and Shropshire Council at firstname.lastname@example.org