The gallery is now about £5m over budget
A new Nottingham art gallery is facing a further £3.25m cost overrun, the city council has confirmed.
Nottingham Contemporary, on Weekday Cross will cost more than £19m, against an original estimate of £14m.
Cost overruns had already added £1m to the project, formerly known as the Centre for Contemporary Arts,
Council leader Jon Collins said he was unhappy with the overspend and admitted the council might have to be "sharper" about costing future projects.
Mr Collins said the extra cost would come from VAT rebates on other projects and would not mean an increase in council tax.
Some of the rising costs have been blamed on problems with building the arts centre on a steep site next to the tram line in the city.
We will be having a full review of this and seeing what lessons we need to learn
Jon Collins, leader of Nottingham City Council
The economic downturn has also had an impact, he said.
He added the Arts Council and East Midlands Development Agency had both backed the project along with private sponsors.
"Major building projects like this do carry their risks - some financial - and the city council has brought in £12m from a variety of sources to finance it."
But he admitted the extra costs were "a huge amount of money" and questions would be asked.
"We will be having a full review of this and seeing what lessons we need to learn.
"I think one of those is that we need, frankly, to be a good deal sharper about how we estimate the cost of projects."
Gary Smerdon-White, chairman of the Nottingham Contemporary, defended the project, which has faced criticism over the building's design.
"The Lace Market is a wonderful diverse set of buildings, it has got everything from Medieval through to Georgian and Victorian times.
"And if you stand in front of the it and look around, at the chapel, looking at the Georgian buildings and looking straight onto the front where we have a massive picture window, it just fits in and blends so well."