Scheme had been due to be completed by end of September
Work is set to continue on Douglas promenade into October according to the contractor in charge of the project.
Auldyn's four-week work plan, published on the MyProm website, shows the scheme continuing beyond its end of September deadline.
It outlines plans for a nighttime road closure between Victoria Street and the Sea Terminal from next week through to 8 October.
Footpath paving, kerbing at the Gaiety Theatre and rail corridor works are also scheduled to run into next month.
The Department of Infrastructure announced in July that the project would be finished by the end of this month, just over three years after it began.
Manx Radio has contacted MyProm and the Isle of Man Government for further details.