It is understood only one potential bidder for the work has so far come forward.

Aberdeen City Council issued a contract notice for the flagship City Centre Masterplan project, which has an estimated construction value (excluding VAT) of £19 million, back in July.

The design includes a new walkway from Union Street; landscaping and lighting; pavilions on Union Street, Union Terrace and Rosemount Viaduct; and the refurbishment of the Union Terrace arches.

The local authority had hoped work would begin on the redevelopment this autumn but a contractor for the work has yet to be announced.

In a report to the city’s growth committee, councillors are told the tender period for bids has been extended “to allow the bidders to finalise their responses”.

It adds that officers “are continuing to assess the outcome of the procurement process” and that a report will be submitted to a future meeting.

The council said it now hopes to announce the successful bidder by the end of the year.

A spokesperson said: “In awarding the construction contract it is vital that the council continues to work diligently to secure best value for the city.

“The council hopes to announce the successful bidder before the end of the year and looks forward to progressing a project that will act as a catalyst for further transformation across the City Region.”

Plans by LDA Design, which include water features, a golden “halo” suspended above the central grass area, shops and cafes in the arches and community gardens along the rail tracks, were unanimously approved in March.