A section of the lower Stuart St block, directly down from the Octagon, will be closed to vehicles in May after upgrades on the neighbouring street begins in April.
Foot traffic access will be maintained.
DCC general manager climate and city growth Scott MacLean said the main purpose of the Bath St upgrade was to replace degraded underground pipes, some which date back to the 1800s.
These include a watercourse pipe along with stormwater and sewer pipelines.
Once the new pipes are installed, the road surface of the street will be upgraded to make it more pedestrian friendly.
The majority of the work will take place on Bath St and within the intersections of Bath and Lower Stuart St, with "most" of the block needing to be closed for construction activities.
It will also affect Moray Place, near the Great King St intersection, and the intersection of Bath and George Sts.
Mr MacLean said the work had been coordinated to reduce the disruption to businesses as much as possible, including starting the project at the end of the cruise ship season.
"However, we acknowledge that the work will still be disruptive and we’re working closely with property owners, tenants and residents to minimise inconvenience," he said.
In December last year, the Dunedin City Council (DCC) voted 10-3 to approve a $1.5 million moderate upgrade to the street, after voting 9-4 against a $2.63 million "high level" option.
It also paid nearly $700,000 to acquire a popular Moray Pl cafe, Side-on, in order to connect pipes between Bath St and Moray Pl.
Time was an important factor in the upgrade project and "almost all" pipe routes had to pass underneath the cafe, so it was forced to close.
A partially collapsed watercourse pipe also ran underneath the cafe and was releasing stormwater, which the council said had the potential to create a sinkhole.
