Officers arrived on the scene near the junction with Holyrood Street at around 22:00 before the entire street was sealed off to members of the public.
Island Echo understands an ambulance also attended the scene, but it remains unclear if anyone has been injured and if so, to what extent.
Police have now established a scene guard at either end of the road and an inner cordon has been set up surrounding a residential property.
Hampshire Constabulary are yet to comment on the incident.
UPDATE SUNDAY @ 00:49 – The cordon has been removed and the road re-opened to both pedestrians and traffic.
Further information is expected later today.
UPDATE SUNDAY @ 13:34 – Hampshire Constabulary have confirmed that a man in his 70s has died. Read more at http://www.islandecho.co.uk/man-found-newport-street-dies-hospital/.