A council worker who had bleach thrown in his eyes and was held at knifepoint in a highway robbery may have been the victim of a random attack.
Police say they are yet to establish a motive for this morning's attack in Northland and appealed for information about two men who carried it out.
The victim, a 45-year-old Northland Regional Council employee, was driving on State Highway 10 about 7am when he pulled over after a vehicle behind him flashed its lights near the Oromahoe Rd turnoff, about 10km south of Kerikeri.
Detective Sergeant Sam Bindon said the council worker was assaulted by at least two men on the side of the road.
He was threatened and a knife was held to the side of his face, leaving him with cuts.
Police said the man's assailants took his cellphone and wallet.
They threw bleach into the man's eyes and face before driving off towards Pakaraka.
Mr Bindon said it wasn't know if the victim would suffer permanent sight damage.
A spokeswoman for the Bay of Islands Hospital in Kawakawa said the man was discharged tonight.
"Police are investigating the incident and are exploring a number of possibilities regarding any motive for the attack,'' police said in a statement.
"The victim was unable to get a description of the offenders, but described their vehicle as white or possibly silver, with a flat bonnet that sloped down, similar to a Honda Prelude or Honda Accord.''
The victim was driving a white Nissan Nivara four-wheel-drive with Northland Regional Council written on it.
A spokesman said council management had been in contact with the staff member's family and would be providing support to them.
He would not comment as to who the staff member was or his role at the council.
Police have appealed for information from anyone travelling on State Highway 10 between Waipapa and Oromahoe Rd between 7am and 7.40am who may have witnessed the incident.
Anyone with information should contact Kerikeri Police on 09 407 9211 or Crimestoppers on 0800 555 111.
Dr Michael Beasley, a medical toxicologist at the National Poisons Centre, said it was most likely the bleach attack would not cause permanent damage to the man's eyes.
He said it depended on the concentration of the bleach and how quickly it was flushed from his eyes.
"If it was just domestic bleach there would be pain and irritation but the injury wouldn't be too bad. But if it was the more commercial bleach there is a risk of more severe injury,'' Dr Beasley said.
"I would imagine that [he would still] probably recover but it might take a matter of several days.''
Industrial-strength bleach could have the potential to cause significant eye damage, Dr Beasley said.