A cyclist told police he was shot at from two vehicles near Omarama in Otago on Sunday night.
Community Constable Bruce Dow, of Oamaru, said the rider reported the incident on the 400m stretch of SH8 between Broken Hut Rd and the Omarama Stream Bridge.
The cyclist, in his early-60s, who declined to be named, said he had turned right from Broken Hut Rd on to SH8 towards Omarama at about 5.15pm, when two vehicles overtook him at speeds between 70-80km/h.
He said a passenger in the first vehicle - a black Mitsubishi Lancer - fired two shots, which were followed by a further shot from the same position within the trailing off-white Toyota Hiace van.
The man was taken aback as he heard the bullets fly past.
"I just couldn't believe that someone was shooting at me," he said. "It was one of the worst experiences I've ever had."
The man had dropped his head to use his helmet for protection from the bullets, then saw a volley of shots fired from the vehicles into trees at the Omarama Top Ten Holiday Park.
"I could hear the shots shredding the leaves of the trees - it was serious stuff," he said.
The man had held a firearms licence for "some time" and Mr Dow believed he knew the difference between a "shotgun bang, a rifle crack and the sound of an air-rifle" - and believed the weapon involved to be a rifle.
After being fired upon, the man continued cycling towards Omarama, where he rang police about 5.30pm with the details of the black Mitsubishi, which he had spotted stopped at the Mobil garage.
He said he would do things differently if he had his time again.
"I wasn't thinking clearly enough. I had a cellphone in my pocket, I could have taken a photo,'' he said.
"They saw me and that made them bugger off, I'd say.''
Const Dow said the Mitsubishi left Omarama for Twizel, where it was stopped by police and searched. No weapon was found and those questioned denied any knowledge of the incident or association with the occupants of the off-white van, he said.
Inquiries are continuing, and anyone with information about the van is encouraged to contact police.
The man said he wanted justice to be done.
"I'd obviously like them caught - they're just a menace to society."