A man has been arrested outside Highpoint Homemaker Centre after a parking spat left another male driver hospitalised, in Melbourne's north-west.

A Victoria Police spokeswoman said the two men were believed to have been involved in a fight outside the shopping centre during Boxing Day sales just after 2:30pm.

One caller to 3AW who witnessed the attack unfold said the two men were screaming at each other.

“There was one bloke reaching into another car taking swings, next minute he’s down on the ground with a bit of blood on him,” he said.

“Next thing the driver is yelling, ‘He took my spot, he’s trying to take my spot!'”

Ambulance Victoria confirmed a man aged in his 40s was taken from the scene to the Royal Melbourne Hospital in a stable condition with upper body injuries.

The reason for the dispute is yet to be determined by police.