Evesham's Abbey Bridge closure extended into December
A Worcestershire bridge due to be closed for 10 weeks will now be shut for a further three weeks.
The project to replace Abbey Bridge, Evesham, as part of an £8m scheme started in September.
Councillors said the bridge was of "paramount importance" and expressed disappointment as it was announced it was not expected to reopen to vehicles until 20 December.
Contractor Hochtief is yet to comment further on the delay.
A temporary diversion will remain until the bridge and viaduct reopen fully.
Councillor John Smith, Worcestershire County Council cabinet member for highways and transport, said: "The news from Hochtief came as a real surprise as we understood work had been progressing well.
"I am very disappointed. Getting this link open as quickly as is possible is of paramount importance."
Mr Smith said a bus fare offer would remain while work continued and an extension of a car park discount scheme for Evesham would be considered, to "help the town and its traders".
A temporary bridge is open for pedestrians and cyclists.