The reopening of the revamped Aberdeen Art Gallery has been delayed by at least a year, the Evening Express can reveal today.

The gallery, Cowdray Hall and the Remembrance Hall – which are currently closed as part of a major £30 million redevelopment – were expected to reopen at the end of this year.

But Aberdeen City Council today said it now won’t be completed until late 2018 or early 2019.

It is understood the project, which council chiefs vowed will make the attraction among the “best regional galleries in the world”, is facing a significant financial overspend.

Councillor Alex Nicoll, the SNP group’s finance spokesman, has hit out at finance convener and council co-leader Councillor Douglas Lumsden.

He said: “It appears that our new Tory finance guru has decided to keep faith with traditions of the previous administration by overseeing yet more delays on the Art Gallery.”

He said Cllr Lumsden needed to explain why there had been delay.

He added: “On his brief watch we’ve already seen Provost Skene’s House ignored, the Tall Ships scrapped and Marischal Square opening months late – this record doesn’t bode well for the coming years.”

A report to city council’s finance, policy and resources committee on December 1 will outline the revised schedule, provide further detail on the issues which have led to the extension of the programme and potential budget implications.

Finance convener Douglas Lumsden said since the issuing of a bond the council has to be “careful” how it announces financial information and changes to its capital budget.

Cllr Marie Boulton, Aberdeen City Council’s culture lead, said: “High level discussions with the main contractor for the Aberdeen Art Gallery redevelopment, McLaughlin and Harvey, are ongoing to finalise a revised schedule for the project.

“Current indications are that the contractor will conclude work on site in the first quarter of 2018.

“Following the handover from the main contractor a further fit out programme is required before the collections can be returned and the building is prepared for opening to the public.

“The final schedule is subject to the ongoing discussions but it is anticipated opening will be delayed until late 2018 or early 2019.

“This is an important project for Aberdeen and it is imperative that what will be a lasting legacy for the city is completed to the exacting standards required for a development of this significance – but a delay of this nature is unacceptable. It is important the issues with the delivery of the project are fully examined and acted upon.

“Measures have already been taken, with the appointment of specialist project manager Faithful+Gould to represent the council in negotiations with the contractor.

“With any building of this age and complexity there will always be complications which can impact on the programme, and that has been the case with Aberdeen Art Gallery. However, we are in discussions with the contractor regarding the circumstances of the extension to the programme.”