A Waipu invention could cure the summer dust nuisance and shuddering corrugations on Northland's 3036km of unsealed roads.
Gravel Lock NZ director Grant Lewis said the binding process his firm used to produce a hard-wearing unsealed road surface was under patent and the firm, set up two years ago, was expanding to fill orders from throughout New Zealand, the Pacific Islands, Australia, Peru and Iraq.
The process involves watering the road, spreading the binding additive on the surface and mixing it into the road to a depth of 150mm, then compacting it.
"We've done roads carrying 300 trucks a day and they have lasted 11 months without maintenance," Mr Lewis said.
The Far North District Council has tried Gravel Lock on Spains Rd at Awanui, and the company website quotes former council engineer Richard Green as saying it was the best dust-suppression product he had seen, with potential to remedy corrugations and potholing.