Works are being carried out in Old Market Avenue by Southern Water in order to make improvements to the sewerage network.
The road was closed yesterday with diversions in place and while the road has now partially reopened, works are still being carried out.
A spokesman for Southern Water said: “Urgent work needed to be done because of a blockage causing sewer flooding both within and outside a property.
“We’re very sorry about the inconvenience caused when we closed the road on Monday.
“Although the closure has been lifted, we will unfortunately have to close the road again shortly.
“The sewer runs very close to a lamp post and this must be taken down to carry out a full repair.
“We need to liaise with colleagues from other utilities and agencies to ensure removal of the lamp post is done safely - once all sides are satisfied, we will be closing the road to carry out the work.
“We will be working as quickly as is safe and we do apologise for the inconvenience we will be causing.”
The works are currently scheduled to be completed on April 27 by the contractor Cappagh Browne Utilities Ltd.
It comes while part of the Avenue De Chartres car park remains closed as works continue due to flooding.
A power fault on March 28, with a subway pump at the end of South Street, which caused the flood has now been fixed, confirmed SSE.
A spokesman for SSE said: “We would like to thank local residents for their patience and apologise for any inconvenience as our teams carry out emergency repairs to resolve an underground cable fault in the area.”
Although the flood has now been drained the bottom level of the car park is still closed.