The 61-year-old truck driver was waiting on the side of William Hovell Drive, in north Canberra, about 9am on Tuesday when a potato was fired at "point-blank range" from a moving car.

He was hit in the groin and taken to hospital in excruciating pain, where he was given morphine.

"It was horrendous," he said.

Mr McCormack had been standing with a colleague near the roadworks at the Coppins Crossing Road intersection, waiting for traffic controllers to set up after peak hour when he was hit.

"We didn't know anything was going to happen. All of a sudden, all we heard was 'boom'. It sounded like a big car smash," he said.

"The potato itself is about three inches round where it hit me on the jeans. The rest of it's history. I went down to the ground, the blokes tried to help me out, but I was in too much pain."

ACT police said the projectile ricocheted off Mr McCormack and hit a second man, but he was uninjured.

Mr McCormack said: "I could tell you here, sitting here now, it just blew me away that someone could do that."

Although he felt lucky he wasn't more seriously injured, he said his colleagues were disgusted that anyone drivers-by would deliberately harm a road worker.

He said 45 of his colleagues had rung him on Wednesday to make sure he was alright.

The truck driver, who has driven large loaders for six years, said there was little he could do except wait while his groin healed. He thanked his employers for being generous and supportive after the incident.

"They've been fantastic. Everything that I want and need, it's here."

Police spoke to Mr McCormack in hospital on Tuesday and urged those involved to present themselves to a police station. They asked for anyone with information or dash-cam footage to call Crime Stoppers on 1800 333 000.

Mr McCormack said there is footage that shows him standing next to a fellow worker immediately before the attack but no vision that shows the car's registration number.

"I think it was a maroon car," he said.

His family members have appealed on social media for information about the incident, asking anyone with information about the car the potato was fired from to contact police.