Goutam Nayyar of Dickens Inn said Cameron St had been closed in the evenings, making the restaurant significantly quieter than usual.
The completed works - expected to go until November - would result in a larger outdoor seating area but fewer carparks nearby.
"I don't know whether it's going to help us or not," Mr Nayyar said.
Joy from Intec Interiors, who did not want her surname published, said many customers had commented on the lack of parking and she wondered whether the works would encourage people to bypass Cameron St in favour of Okara.
"It'll be a wonderful thing going forward, it's just a matter of getting through it."
Gina Klemke, manager of Merric Apparel said while construction had caused some inconvenience, custom was still good.
"It will have some impact for starters, but for the sake of progress and change we are happy to see it happen," she said.
Work should be completed by November, when a paved "shared space" would extend from the pedestrian mall into James St and another block along Cameron St to John St.
By mid-2016, a transparent canopy would be installed over the intersection of Cameron and James Streets.
The revamp would also include an outdoor stage and new street furniture.