WHEN Singapore set about designing a new arts centre, it was envisaged that it would ''spotlight Singapore as the crossroads of cultures and ideas.'' The architects said it was conceived as a ''symbol of excellence for the arts''. The body charged with developing the centre said their goal was ''an architectural gem.'' However, the words spotlight, symbol and gem have not featured prominently in discussion of the project since the architectural design was unveiled last month. Rather, the main buildings have been described as ugly concrete blobs, styrofoam boxes and marshmallows. Instead of making a dramatic statement, as the Sydney Opera House did, the design is a mundane disappointment, say the critics. To the casual observer, the model of Singapore's cultural icon is remarkably bland and boring - which is a description not uncommonly applied to Singapore itself. In reinforcing the stereotype of Singapore, the design has lent itself to the kind of disparagement that greeted government officials two years ago when they announced plans to make the republic a global city for the arts. How could a city state devoted so much more to commerce than culture conceivably become an internationally-renowned leader in artistic activities? the critics asked. But the Government has been beavering away with some success to counter the criticism, persuading international auctioneers, art galleries and producers of top entertainment to bring their wares to Singapore. The arts centre, named, rather awfully, The Esplanade - Theatres on the Bay, is intended to be the focal point of Singapore's cultural activities and attract performers from other Asian countries and from around the world. Some artists have complained that the money for the centre would be better spent on assistance to existing groups. But the Government believes that by creating an arts infrastructure it will encourage more Singaporeans to become artistically creative. The centre is an ambitious enterprise, featuring five distinctively different theatres in what is described as a park-like setting, with garden courtyards and a terraced landscape on the waterfront at Marina Bay. The concept of theatres catering to everything from symphony orchestras to Chinese opera and from drama to poetry reading, has been widely applauded but the schematic design has sharply divided architects and the community at large. President Ong Teng Cheong, a former architect, gave the design his imprimatur by saying he was ''quite proud'' of it. But this did not stem criticism. The bluntest put-down of the project, which is expected to cost S$1 billion (about HK$5.1 billion) by the time it is completed in 2000, was contained in a letter to The Straits Times. The writer said the design was ''frightfully ugly''. ''It has no cultural characteristics and absolutely no character,'' the writer said. We certainly do not need more concrete blobs with no architectural beauty. An arts centre we can be proud of should reflect our cultural heritage.'' The letter writer's criticism was dismissed by President Ong, who said opinions on such matters were subjective. But a week later, Tay Kheng Soon, a former president of the Singapore Institute of Architects, delivered a detailed critique of the design in The Straits Times, which said the ''ungainly shapes and size'' of the three main performance halls were ''the bane of the design both architecturally and culturally''. Mr Tay, who is also a former chairman of both the Singapore Planning and Urban Research Group and the Heritage Committee under the Advisory Council on Culture and the Arts, said a ''certain mundane-ness'' had crept into the design, which he sensed had been ''done in some desperation to meet the demands placed on it''. He said he did not sense any uplift in the mood of those who saw the design exhibition and who attended the talks that followed. He was also critical of the fact that the ''huge structures'' for the western arts were allowed to ''overshadow actually and symbolically the diminutive Asian arts performances spaces''. ''I fear that the historic moment that this project presents to Singapore to interject at this juncture of Asia's new age is drifting away,'' he said. A prominent Singapore poet, author and journalist, Koh Buck Song, said he was disappointed when he heard the arts centre's planners were not aiming to create a national symbol. ''Whether the arts centre can meet the needs of users and viewers inside and whether the community can relate to it as part of their lives are important factors,'' he said. ''But this is surely also a chance to come up with a design that will express the national spirit and clutch at our hearts.'' He said the design was not distinctive and inspiring enough to be remembered and ''certainly not as memorable as the Sydney Opera House''. Calling for changes, he said that with four times the amount of money spent on the Sydney Opera House available to the centre and with creativity and expertise at hand, Singapore could ''surely do just as well, if not better''. The architects, Singapore's DP Architects and Britain's Michael Wilford and Partners, rushed to the defence of their design. Koh Seow Chuan, a director at DP Architects, said the main buildings' external walls would be ''rich with textures''. He said the model could not show in great detail the external treatment. At the same time, Raymond Woo, who chaired the project's design and aesthetics advisory group, said the detailed design of the skin or cladding covering the two main concert halls would be studied further. ''We need to have a bit of patience,'' he said. ''People should not jump to conclusions that it will look like a blob.'' While there is some cautious optimism that the centre will eventually achieve recognition as a pantheon of the performing arts, many people in senior design and arts positions remain unhappy with the project's appearance. A top official involved in the advisory process privately expressed reservations about the design but demurred when it was suggested he might press for changes. ''It will be very difficult for the Government to make any move to have the design revised now it has been officially unveiled and approved,'' a leading critic said. ''I'm afraid we're stuck with our blobs on the bay.''