Welsh politicians have warned their Cardiff assembly's HQ could become the regional equivalent of the millennium dome after the announcement of a financial probe into the much-delayed project.

The planned building for the devolved institution was originally intended "to be outward looking, with a strong national identity, [to] express the status of the assembly and be instantly recognisable as the new political forum for Wales" but the venture has been dogged by rows, hold-ups and spiralling costs.

Leader of the Welsh Conservatives in the national assembly, Nick Bourne called on first minister Rhodri Morgan to scrap the building and to take "a lead in putting the needs of Wales before political egos".

"It is high time that the Lib Lab coalition put an end to this fiasco surrounding the new building in favour of spending the money on public services," he told ePolitix.

Lib Dem AM Eleanor Burnham warned that unless the assembly was careful the building was as "domed" as a certain notorious Greenwich visitor attraction.

"Are we not in danger of being perceived to be exactly in the position as the dome became - a huge white elephant of complete mismanagement and a history of inadequacies and lack of control and monitoring?" she said.

The original budget for the state of the art building was set at £26.6 million, but this has soared to an estimated £37 to £47 million and no work has been carried on the project since July, with completion already two years behind schedule.

A second report by the auditor general for Wales, Sir John Bourn, will aim to get to the bottom of the 1998 scheme to house the Welsh assembly after an earlier probe which heavily criticised disgraced former Welsh secretary Ron Davies.

Announcing the new investigation, Bourn said that spiralling problems had been compounded by the assembly's costs row with and sacking of architect Lord Richard Rogers.

The watchdog gave a grim assessment of progress so far. "It does seems likely that the new building will be smaller than originally envisaged and it will cost a good deal more than originally thought of and it will be available much later than originally planned," Bourn said.

Earlier this month, Paul Hyett, president of the Royal Institute of British Architects, described the assembly's treatment of Lord Rogers over the past 12 months as "farcical".

Welsh finance minister Edwina Hart has welcomed the auditor's intervention and an assembly deadline for companies interested in taking over the project expired on October 31.

An assembly spokesman told ePolitix that there had bee a "good response" to the competitive tenders and that a decision could be taken to move the project forward at the start of next year.