Police were called to Edge Hill, a suburb of Cairns, on Thursday afternoon after a black Audi crashed into the back of a white vehicle and one person was shot before all involved left the scene.

Witnesses told officers a man got out of the white car and spoke to another man in the black Audi before shooting him.

"One of the occupants of the black vehicle appeared to be wounded. He was helped back into the vehicle by a female he was travelling with," Detective Acting Inspector Jason Chetham told reporters on Thursday.

"They left the scene quite quickly."

Officers found the black Audi nearby which sparked an emergency declaration urging people to avoid the scene.

A home was searched by officers and it is believed the occupants, who were not there at the time and are known to police, are connected to the incident.

Two people, including a man with a non-life-threatening gunshot wound to the leg, were located by police on Thursday night and are helping with the investigation.

A search continues for a third person, believed to be the gunman.

He is described as being about 30, slim build, about 182cm tall and 90kg, with a tan complexion and short black hair.

Members of the public are urged not to approach the man and to call police if he is spotted.

Australian Associated Press