Contingency crews based out of Drill Hall Road in Newport were called to the scene at around 22:30. The 999 call came shortly after the town went into darkness following a power outage, although it is currently unclear if the two are related.
Non-FBU firefighters have entered the building on Pier Street wearing breathing apparatus and are using a hose reel to tackle the fire, which is not believed to be serious.
Two pumping appliances are in attendance with extension ladders being taken into the supermarket.
The road is currently blocked and a cordon has been put in place.
UPDATE @ 23:30 – Southern Vectis buses are currently unable to serve Albert Street or the Boots bus stop and are advising passengers of Route 3 buses in either direction to make their way to the Central Car Park bus stop.
UPDATE @ 23:51 – Residents living above the food store have not been evacuated.
Reports suggest smoke was seen coming from the rear of the building, possibly relating to cooling units.
UPDATE @ 00:10 – Firefighters have now left the scene of the incident and the road has fully reopened.
A faulty chiller unit has been identified as the source of the smoke.
Firefighters across the Isle of Wight and throughout the country remain on strike until 18:00 tomorrow (Tuesday).