SOUTHERN Water has apologised for an 'unpleasant smell' wafting through Southampton.

Residents in St Denys have reported an "awful smell" in the area to the water company.

They say the stench began sometime during the weekend - but added that it is not the first time they have been plagued by the smell.

The pong can be smelled from homes in the area and also by passing motorists using Thomas Lewis Way.

READ MORE: Residents disgusted after smell like 'festering, hot sewage' plagues Southampton

Southern Water has since apologised for any "distress" caused by the smell, blaming it on a "build-up of sludge" at its  Portswood Wastewater Treatment works.

Southern Water says the sludge build-up was caused by a technical fault and said it is working to remove it.

A spokesperson for Southern Water said: “We are aware of reports of an unpleasant smell from our Portswood Wastewater Treatment works in Southampton, and we would like to apologise for any distress caused.

“We recently invested £5.5m on this site to tackle potential impact on the local environment, including odours, but unfortunately a technical fault has resulted in a build-up of sludge.

READ MORE: Southern Water: No water supply in Southampton again

"We are already removing this, and expect the smell to fade as this is carried out.”

It comes just days after Southern Water agreed to pay out £3 million to compensate those affected by a water outage last week.

Around 13,000 homes and businesses were left without water when an issue at Southern Water's Otterbourne site disrupted supplies.

Homes in Southampton, Eastleigh, and Winchester were affected.