Police in Barcelona have shot at a man driving a stolen truck loaded with butane gas canisters at high speed towards a road encircling the city.

The vehicle was reportedly stolen, and as it sped towards Barcelona pursued by police gas cylinders fell out, injuring a passer-by.

The vehicle was stopped as it drove the wrong way onto a slip road by a police officer who shot at its windowscreen.

Police named the man to local media as Swedish citizen Joakim Robin Berggren, born in 1984, who could have acted under the influence of drugs.

He was uninjured in the shooting and has reportedly been arrested, with authorities evaluating his mental health. The incident is not terror-related, said police.

Mireia Ruiz, a woman who saw the incident from her home nearby, told AFP the driver ignored people screaming at him to stop as he sped down the wrong side of the road.

"When people shouted at him, he would laugh and make offensive gestures with his hand," she told the agency.