Phil Pinder, director of York Business Improvement District, said they were “gobsmacked” to see the security barriers being lowered onto the street late on Tuesday night.
The barriers are a temporary measure to protect people from hostile vehicle attacks in the run up to Christmas, but Mr Pinder said there had not been adequate consultation.
The barriers will hinder around 30 delivery drivers a day accessing the Pavement end of the street, Mr Pinder said.
The co-owner of The Potions Cauldron added: “If there’s a terror threat there, the city needs to be protected and I fully understand that, but it needs to be designed so it works for the city.
“It can’t hinder the normal day-to-day behaviour of the city, otherwise they’re actually giving in to terrorism.”
Disability advocacy groups have also hit out at the measure, saying it makes a tricky street even more difficult to navigate.
The King’s Square end of the street is not blocked, but Mr Pinder said having delivery drivers reverse all the way down the street would require a banksman, at extra cost.
Mr Pinder questioned why the Shambles could not have staffed barriers that could be moved for delivery drivers like other areas of the city.
“I think they’ve really messed up on the design here,” he added.
City of York councillors will next week debate measures that would see more subtle anti-terror measures being installed around the city’s footstreets, which would eventually prevent the need for temporary barriers in the Shambles.
“The location plans for the barriers were drawn up and agreed by national counter-terrorism security advisors and York Council’s highways team, who are experts in their field.
“Make It York and York City Council’s priority is to ensure the safety of our residents and visitors throughout the festive period.
“The installation of the protective security barriers is an important measure to protect our city during this time.
“In regards to the Shambles specifically, the Shambles is still accessible from the other end and there are additional disabled access ramps being installed from the barriered end.
“Make It York gave prior notice to affected businesses on the Shambles ahead of installation with hand delivered letters.
The spokesperson added: “Again, we appreciate the inconvenience this may cause and we’re continuing to work with local businesses and residents to support them with any concerns.”