The cost of Glasgow's new publicly funded transport museum has risen by almost 50%.

The proposed riverside project will now cost £74m, up from the initial £50m estimate when it was first approved.

The extra £24m came to light as Glasgow City Council moved to approve the main contractors for the project, which will sit on the north banks of the Clyde just down stream from the SECC.

Last autumn the architect behind the scheme, Zaha Hadid, was told to investigate ways of cutting the cost after it has risen to £60m. Saving were already made by replacing aluminium cladding with zinc.

Next week, Glasgow City Council's executive committee will decide whether to approve the appointment of builders HBG Construction and an increase in capital funding of £14m, taking the total budget to £74m.

The reasons for the budget rise are given as inflation in the price of core materials, lack of competition in the construction market and the detailed design of the building.

Some members of the committee are enthusiastic about the design and the benefits of the new building at the Glasgow Harbour development.

Ground on the banks where the River Kelvin meets the River Clyde at the old Yorkhill Quay is already being prepared and major road works constructing access roads and an interchange at the Clydeside expressway are under way.

Councillor Archie Graham, executive member for Culture and Sport Glasgow, said: "The museum will very quickly become a vital part of Glasgow's cultural life, a world-class museum and visitor attraction in a world-class city.

"While there has been inflation in the costs of the project, we now have a clearer picture of the ultimate cost.

"We are not prepared to accept that there are parts of Glasgow which are simply too difficult to regenerate, as long as there is any chance of bringing previously derelict land back into use and delivering new facilities for Glasgow."

Others are more sceptical about the need for high profile designs. John Mason, SNP group leader, said: "There are major concerns about the costs. It is unacceptable.

"Yes we want nice buildings but these innovative designs tend to be the ones that go way over budget. The building is not the important thing. People go to the transport museum to see what's inside rather than the outside."

The museum will replace the transport museum currently at the Kelvin Hall, and will have almost as much exhibition space as the newly refurbished Kelvingrove Art Gallery and Museum.

Council officials stated detailed reasons for the cost increase since the initial 2002 figure, including a rise in the price of steel beams of 25%, overall construction materials of 33% and labour costs have risen by 37%.

Specifically it was explained that the cost of a single panel of anti-sun glass, needed to protect exhibits, had increased from £70 to £115.

Rising costs were given as the reason for scrapping a planned Richard Rogers designed bridge across the Clyde linking Tradeston to Broomielaw. Costs increased from £38m to £60m and eventually a cheaper version, dubbed the squiggly bridge, was approved costing £3.7m.

It is hoped the new museum will be an iconic building immediately associated with Glasgow. Zaha Hadid won the contract after her design with a waved roof won over the selection panel.

Hadid, from Iraq, is the only woman to have won the prestigious Pritzer Prize for Architecture and she has been shortlisted for the British Stirling Prize for Architecture for her design of the BMW headquarters and Phaeno Science Centre, in Germany.