The driver of a Jeep that sped through the intersection of Flinders and Swanston streets just before lunch, narrowly missing pedestrians, is still on the loose.

People watched in horror as a man jumped on to the bonnet of the vehicle as it reached speeds of up to 100km/h with at least six police cars in pursuit.

The man suffered minor injuries when he fell off.

Police believe an argument broke out between the two men, who are known to each other, on Flinders Street about 11.30 when one jumped on the Jeep before it sped off.