The failure has occurred on Melville Street between the junctions of Nelson Street and George Street.
The road, which could well be closed later on this morning to allow repair work to take place, has been lifted around the height of the curb.
Water that is rising up through the road and pavement is gushing down the road onto Dover Street and Bellevue Road, causing some minor flooding.
The burst was reported to Southern Water at 06:30 this morning.
It is unknown at this time if any properties have been affected.
UPDATE @ 09:37 – Island Roads have issued an emergency closure notice confirming that Melville Street has now been closed for a distance of 82 metres.
Southern Water say they have a team on site repairing the burst on an 8-inch main. Local residents may notice some discolouration or low pressure at first; this is completely normal when there’s been a disruption to the supply and is only temporary.
Southern Vectis buses are diverting via George Street until further notice.
UPDATE – Repair works have now been completed and Melville Street has re-opened.