AA district chairman John Unsworth said the branch had made sure NZTA was aware that work done last summer was not up to standard. He said and the agency had assured the AA it would not happen again.
"We'll be watching to make sure that there is no repeat of the problem," Mr Unsworth said.
He said the Wanganui council began investigating the issue after a driver travelling over a newly sealed road had an extreme number of loose stone chips flick up and stick on the underside of the their vehicle.
"A loose stone flicking up on rare occasions is an unfortunate reality of our chip seal roads, but the amount in this case was far beyond the norm when a road is resealed.
"We also heard reports that there was also a big increase in the number of people putting their vehicles in to have cracked windscreens replaced at the time, due to damage from flying stone chips," he said.
Mr Unsworth said chip seal appeared not to have not stuck to the road as it should, due to the way it was applied.
"Now NZTA has given us assurances that their contractors will change their procedures to meet best practice in the future.
"Along with the damage they can do to people's vehicles, loose stone chips are a real safety hazard on the road, especially to motorcyclists, cyclists or pedestrians," he said.
Mr Unsworth said if any motorist suffered damage to their car from stone chips due to the resealing problem they should contact their insurance company in the first instance.
If they cannot resolve things this way, they should contact NZTA.
"It's not right for people to be out of pocket due to no fault of their own, and the roading authorities need to take responsibility for the work not being up to standard," he said.