She and her husband, Rade, who own the RD Opal Centre fronting the Pacific Highway at Korora, want the advisory sign removed and put somewhere more appropriate.
The RTA installed it two months ago, about 50 metres south of the entrance shared by the Opal Centre and the Bananacoast Caravan Park.
The sign advises motorists the Gwydir Highway will be closed 55km west of Grafton from 9am to 3pm Monday to Friday, excluding holidays, until December.
"Why do they need the sign there?" Elizabeth said. "There are more appropriate places for the erection of this sign along this 80km stretch of highway to Grafton.
"It is distracting for drivers, who now not only don't have time to see our sign and are actually driving past us, but they also can't see school buses, motor homes, cars or pedestrians using our turnoff.
"Whoever decided on the placement of this sign in future needs to use their commonsense.
"There's no consistency here, considering the city council last year asked us to remove one of our perfectly good signs south of our business.
That sign had told motorists the Opal Centre was 200 metres away and they should prepare to slow down and change lanes so they wouldn't miss our turnoff.
"It had been there for 22 years but the council suddenly decided it was illegal. We've lost a lot of business since it's come down."
A council spokeswoman said the Opal Centre would have been asked to remove its sign because it was erected illegally.
"Approvals have been required for the erection of signs since the 1950s under the Local Government Act, and development consents were enforced under the Environmental Planning and Assessment Act from 1979," she said.
Late yesterday, the RTA said it would "review the location" of its advisory sign "to determine if it can be moved".