Above-ground construction began on Monday on a 57-storey tower at the north-west corner of Swanston and La Trobe streets, The Age reports — a 185.4-metre high-rise on top of the new State Library station that its developer, Scape, says will be the tallest student accommodation building in the world.

The project, called the State Library Exchange, will put about 1,420 students in its top 46 storeys, with the first nine levels leased to RMIT as teaching and commercial space. The build is costing Scape and its partners more than $500 million; RMIT will pay $190 million over 15 years for its share. Scape co-founder and chair Craig Carracher likens the textured facade to "Rubik's cubes".

The approval nobody got to comment on

The tower's path to a permit is the part that raises eyebrows. Scape received permission in 2017 directly from then-planning minister Richard Wynne, because the site sits within the Metro Tunnel planning framework — bypassing Melbourne City Council, with no public notice period and no community consultation. The Office of the Victorian Government Architect and the council did work with the developer on design and technical requirements, and the council now refers questions about the approval to the state government.

"We're approving homes where people want them — close to jobs, transport, universities and services," a state government spokesperson said. Norman Day, an architect involved in university campus design, saw it differently: he was surprised there had been no community input into a building of this scale. "It's a huge building in a very delicate part of the city in an important intersection," he said. "A city is designed for its people, and so it seems to me a lost opportunity to get the best value for people."

On the library next door, the design carries its own answer: three towers of varying heights arranged to avoid extending the existing overshadowing of the State Library forecourt. The plans show the building will cast a minor shadow of its own at particular times of year, mostly falling within the shadows of buildings already there.

A record Scape takes from itself

The world's-tallest title, if the tower claims it, changes hands within the company — the current record holder, per Mr Carracher, is Scape's own roughly 170-metre building on Franklin Street. At other Scape sites such as 50 La Trobe Street, studios start at 16 square metres, with two-person apartments at 25.

The timing is its own story. International student numbers in Australia have been declining, and federal Labor is under pressure from the Coalition and One Nation to cut them further. Mr Carracher's counter: Australia has about 80,000 purpose-built student rooms and needs "at least another 100,000" — and, he argues, every student in one is a student not competing for a rental. "They're not going into housing in Carlton, they're not going into housing along the suburbs on the train lines," he said.

Scape had originally hoped to finish the building two years after its 2017 approval; the Metro Tunnel works intervened, and nine years on the cranes are finally above ground. RMIT vice chancellor Alec Cameron, whose university will fill the lower floors, explained why the university wants a different kind of space: "Large lecture theatres were built for a different model" — smaller groups, flatter floors, more flexibility. The students it houses, though, can come from anywhere: the accommodation is open to all, with the tram and train network — and the station beneath it — doing the rest.