Business owners affected by the New Street closure were given minimal new information at a meeting with stakeholders on Thursday morning.
About 20 locals heard from representatives from Roads and Maritime Services (RMS) and Daracon, and were told that no changes to the potential six-month closure were possible.
Business owners voiced their concerns about the effect on their trade, but these were met with apologies.
Transport for NSW northern regional director Anna Andrews said it was important for her to be "upfront and transparent" when delivering the bad news.
"I appreciate it's very difficult, but I think it's important people understand what can and can't be changed," Ms Andrews said.
"Unfortunately, we're in the situation where nothing can be moved."
Ms Andrews said businesses that lost profits during the closure would be able to put in an insurance claim against the RMS, an idea that interested many attendees.
Gunnedah mayor Jamie Chaffey said the business owners were very "time-poor people" and asked if the RMS would assist with the claims process.
Ms Andrews said it was "not something we can help you do".
"It's not appropriate for our organisation to be involved," she said.
Business owners and Cr Chaffey said they were disappointed the signage to attract passersby to stores was not prepared in time for the closure.
Gunnedah Veterinary Hospital's David Amos said the signs were "totally inadequate" in size, and hoped bigger ones would be developed.
"Having multiple signs that are quite large and have lots of different logos could become a safety hazard if people are trying to read multiple signs," Ms Andrews said in reply.
"We need to work together to develop a plan on what the signage looks like."
Ms Andrews said the RMS would also work on social media posts to inform residents.
They would "talk more broadly that the road network is changing and that there are businesses" that still need customers.
A further meeting will be held to discuss in more detail the project plan and timeframes for the two stages of the project.
The entire Gunnedah bridge project is expected to be finished in 2021.