Officers are attempting to locate 5 males who were involved in the brawl at the roadside on the southbound carriageway of Medina Way leading onto Coppins Bridge. The incident, which was captured on camera, occurred at around 18:20 and involved two separate vehicles.
Police did attend the incident but the group had dispersed upon arrival. No arrests have been made.
A passing motorist captured the entire fight on an in-car dash cam, which can be viewed below.
Anyone with information is asked to contact PC Stephen Quelch of the Newport Safer Neighbourhoods Team on 101 .
UPDATE THURSDAY: The Youtube video has now been removed by the user.