A three-way, single-lane intersection is in the process of being constructed at the intersection of Tarbert St, Centennial Ave and Dunorling St.
A pedestrian crossing on Dunorling St is also being moved further towards the new roundabout as part of the work.
New Zealand Transport Agency (NZTA) Central Otago area manager John Jarvis said the work was unlikely to be finished until mid-November as Central Otago District Council (CODC) was using the opportunity to improve water mains.
"Everything's basically on track; it's just the fact the water services have to go in first so that's had an impact on the programme," Mr Jarvis said.
Initially NZTA had not known about the work which needed to be done on the pipelines, he said.
"It was [October] always going to be an ambitious target date . . . that was what we hoped to target initially before we started.
"The actual roundabout hasn't changed."
Fulton Hogan staff who had been contracted to do the work were doing kerbing work at present, he said.
"We've done a lot of work to fast-track everything as much as we can."
CODC manager of assets and contracts Murray Washington said a decision was made to undertake improvement work on Dunorling St and close off some mains while the work was being done on the roundabout.
"The utilities work directly affecting the roundabout was programmed and completed in five working days . . . any work affecting their programme was complete [on] October 2," Mr Washington said.
A working arrangement between the contractors Fulton Hogan and Delta Utility Services had been established under the guidance of NZTA, Opus International Consultants and CODC, and the work, estimated to cost $130,000, was being paid for from existing Alexandra water supply renewal budgets, he said.
Utility pipes in the vicinity of the roundabout needed to be upgraded to 300mm and 150mm pipes.
An area on the road that had recently been re-surfaced in nearby Ennis St had needed to be dug up.
"The footpath was going to have to be modified to suit the new pedestrian crossing and kerb alignments and also to blank off redundant mains in and between Tarbert St and Ennis St.
"The full ramifications of redundant pipes in Tarbert St weren't known when Ennis St was resurfaced 12 months ago.
"To achieve the best result we need to blank off some lines at Ennis St."
The NZTA tender allowed for the work on the roundabout to be completed by early December.
