Shotter said workers on the ground have occasionally given updates but that's about where it stopped.
"NZTA have been hopeless as far as communication goes, weekly updates from NZTA were agreed to but that hasn't happened."
Alan Luoni, who owns Al's Autos, said the work has been a massive headache for his business.
"I used to use the office at the front of the building, one afternoon my landlord came in and told me I had to move everything into the small workshop at the back because the next day contractors were moving in," he said.
"That was the first I heard about the job."
Like Riverside Mowers and Machinery, Luoni has also struggled with communication from NZTA, and said it's been poor.
"It's too late for NZTA to step up communication now, I think they should have come and seen all the houses and businesses around the area and talk to us personally first, to find out what effect it was going to have on us."
Luoni estimated his business was down by about 64 per cent because of the roadworks.
"The worst thing about it is considering rents around Whanganui, I can't just move from here and go somewhere else. Admittedly I've got a fairly good deal on the rental, but that doesn't offset the fact that we're way down on business," he said.
"Winter is hard enough as it is, come back in September and I might not be here."
NZTA has been approached for further comment.