It is hoped a new lane will relieve rush-hour congestion at an inadequate one-lane roundabout on Whangarei's Riverside Drive.
Whangarei District Council roading manager Jeff Devine said original designs of the intersection of Dave Culham and Riverside drives allowed for a two lane roundabout.
However, investigation showed the ground sits on up to 25 metres of soft marine mud, meaning the cost of improving the ground to accommodate the full-size roundabout will put the project over budget by $1 million.
"The decision was made by council to only construct the current single lane roundabout initially, as the second lane for the roundabout could be retro-fitted," Mr Devine said. "[Council] intends to install a left turn slip lane on the Onerahi to City approach leg to the roundabout, turning onto Dave Culham Dr," Mr Devine said.
"It is anticipated that these works can be fitted into the original footprint of ground improvement works completed as part of the original construction project."
