The part-pedestrianisation of Aberdeen's Broad Street may not be completed until next summer after workers hit unforeseen problems.
Contractors started work in May but their 32-week schedule was hit when a seam of soft peat was discovered under Broad Street.
Then water pipes were found to be damaged and blocked.
The council is prioritising work in nearby Upperkirkgate. Compensation is expected to be discussed.
Upperkirkgate, which was originally due to reopen to traffic in August, will not now be open until December or January.
Retailers there have told BBC Scotland their trade has been hit by the continuing closure and lack of certainty about what is happening.
The authority said the final phase of the work, to install a water fountain and raised area immediately outside its Marischal College headquarters, is not expected to be finished until late spring or even early next summer, depending on the weather.
An Aberdeen City Council spokeswoman said: "We apologise for any inconvenience this may cause to customers in the area and we are working closely with the contractor to try to re-open Upperkirkgate and Broad Street early where possible."
Meanwhile, a temporary surface will be laid to allow this year's Christmas Village to be held on Broad Street.