Emergency services are currently on scene at South Street next to the pedestrian crossing outside Morrisons supermarket.
Island Echo understands that the Route 9 double decker left the bus station at around 20:40 but just moments into its journey became involved in a road traffic collision.
The front windscreen of the bus has been smashed on the near side.
Police have cordoned off the scene as investigations into the incident get underway. No arrests have been made.
South Street is expected to remain closed between Furrlongs (Cineworld) and Church Litten for the next couple of hours as doctors carry out their initial assessment of the woman’s injuries at St Mary’s Hospital.
UPDATE @ 23:05 – Simon Moye, Southern Vectis’ operations manager, has tonight issued a statement:
“One of our vehicles was involved in an incident in Newport earlier this evening when a pedestrian stepped in front of the bus.
“The pedestrian was treated by paramedics at the scene, and taken to hospital. At this stage we do not know the extent of their injuries, but we are monitoring their progress and wish them a full and speedy recovery.“We are providing support for our driver. We are also assisting police as they carry out their enquiries.”
UPDATE SUNDAY @ 07:00 – It is understood that the casualty has been airlifted to Southampton General Hospital suffering from a bleed on the brain.