Brighton Rd at Westwood, Dunedin, will be closed from 9am today for three or four days as contractors work to fix it.
The closure will mean an extensive detour via Saddle Hill Rd and Scroggs Hill Rd.
Water and waste services network contracts manager William Clifford said the council received reports from members of the public on Tuesday evening of water and sewage on the road, and from a resident who had a toilet ''bubbling up''.
Contractors went to the site and found a blockage in a pipe running underneath Brighton Rd.
The job was ''bigger than usual'' as the pipe was deep, and relatively large.
Its location near the beach meant sandy conditions, so the council needed to be ''careful and organised'' in its response.
Mr Clifford was confident there would be no effect on the environment from the work.
He said residents would be able to use their facilities while the work was done.
The road was down to one lane yesterday while pumps were installed to remove wastewater from the site. They would run throughout the repair period.
All wastewater from the site was being taken to a pump station, and there had been no overflows.
The council apologised for the inconvenience the repairs would cause.
''Staff and contractors are working as quickly as possible to complete the repairs and get the road back to normal.''
Bus routes would also be affected.
The Otago Regional Council said Brighton-Green Island buses in both directions would travel as far as Green Park Cemetery on Brighton Road then passengers would disembark at the roadblock and walk around it to another vehicle that would complete the journey to Brighton. The same principle applied for buses running in the other direction.
The ORC said there could be delays.
