A major blockage and damage to a pipe are being blamed for last Friday's flooding at Magherafelt's Meadowlane shopping centre.
It is understood that some clearance work has been carried out at Moneymore Road junction with Queen's Avenue and will continue on Monday.
Motorists are advised that the work could result in lane closures for a time.
There are also discussions about the erection of a wall along the side of the shopping centre to prevent water flowing in to the underground car park from the roadway.
Local DUP MLA Keith Buchanan, who held a site meeting with NI Water and the Department for Infrastructure and Meadowlane management, said today that "several failures" were identified.
He said the department had agreed to upgrade the gully at the junction.
"Although we welcome the identification of issues and the swift response to rectify these issues we also stress that no reasonable infrastructure will be able to cope with substantial rainfall in a short period of time as experienced recently," said Mr Buchanan.
He added that he a meeting scheduled for next Tuesday with Rivers Agency to discuss other matters relating to local flooding.
Several business units in the shopping centre were flooded with owners and staff working throughout the night to get them ready for opening last Saturday.