An independent team of consultants will carry out an investigation into the flooding of the Broadway underpass on Belfast's Westlink at the weekend.

Speaking at a special committee hearing in Stormont today, Geoff Allister, CEO of the Roads Service, revealed details of the nature and scope of the investigation, which was announced yesterday by Minister for Regional Development Conor Murphy.

Mr Allister told the committee 'these will be consultants who have not been involved in any way with the work to date on the (underpass) contract ... and the sorts of things I want them to look at will be the whole background, intensity of the rainfall, to establish clearly the cause of the flooding, to look at the design and to look at the construction standards.'

Jim Wells of the DUP asked, why the underpass, which became flooded under 6m of water following Saturday's downpour, had not been closed to the public earlier.

He expressed concern that five cars had been allowed to enter the underpass when it was under 2m of water.

Geoff Allister said he could not explain how they accessed the underpass as the road had been closed.

After the meeting, Ulster Unionist MLA Fred Cobain questioned the current policies that the Executive has in place to deal with torrential rain and flooding.

'The lack of adequate provision is putting property, lives and the economy in Northern Ireland at risk, and unless action is taken quickly similar flooding may reoccur,' he said.