MAJOR drainage defects on Newport's £55million new road system have delayed its opening yet again.

Parts of a three mile stretch of the Southern Distributor Road will be dug up to sort out drains that have been badly laid.

Council roads boss Brian Kemp estimates the faults will mean another month of waiting.

Contractors Morgan Vinci were making final checks when they noticed the flaw, which was made worse by heavy rain.

Mr Kemp, council head of engineering, said: "It's defective pipework that has been laid wrong. Poor drainage is one of the chief destroyers of road structure, particularly the lower layers.

"We will press the contractors to resolve this as soon as possible. None of the extra costs will fall on Newport council."

Mr Kemp said faults were peppered throughout the western half of the road from the new Usk Bridge to Pont Ebbw roundabout.

Morgan Vinci are still analysing the situation but Mr Kemp said: "Repairs will involve digging up drains and replacing them. Some of the road surface could be dug up. This will lead to a delay in the opening of up to a month. It could open at the end of October."

The SDR was originally expected to open in June, but the deadline has been repeatedly pushed back.

Contractors shifted the opening to the end of July, blaming the 'tidying up' of barriers and roundabouts. Then in August it emerged part of the road had sunk by two to three centimetres, meaning 100m had to be pulled up.

There was another headache earlier this month when contractors asked for extra payment to open the road for the Tour of Britain cycle race. It is believed the final bill could be £28,000, which may be split between Newport Unlimited and the council.

Councillor David Atwell, Tory spokesman for transport, said: "The SDR got off to a wonderful start but this is most disappointing. Everything in construction relies on good drainage.

"This gives the wrong impression of Newport."

A spokeswoman for Morgan Vinci, who used subcontractors to lay the drainage, said: "This is all part of our finishing project to ensure a high quality and safe road is delivered."

The SDR is a key part of the city's regeneration strategy.

It will link the M4 at junction 24 to the Pont Ebbw roundabout to divert traffic away from Newport centre and boost access to business areas.