The Victorian Government has approved plans for Australia's tallest building — a six-star, 90-storey hotel and apartment complex to be built by casino operator Crown Melbourne.

Key points: New skyscraper will tower over Melbourne's current tallest building, Eureka Tower

New skyscraper will tower over Melbourne's current tallest building, Eureka Tower The 90-storey, $1.75-billion development will be 323 metres high

The 90-storey, $1.75-billion development will be 323 metres high Development will include upgrades to Queensbridge Square and Sandbridge Rail Bridge

The tower, which will feature 388 hotel rooms and 708 residential apartments, will be built near Crown Casino in Southbank.

It will be 323 metres high — slightly taller than the 322.5-metre Q1 skyscraper in Surfers Paradise, which is currently Australia's tallest building.

Melbourne's tallest building, Eureka Tower, is 297 metres high.

The Australia 108 residential tower, also being built at Southbank, is planned to be 319 metres.

"This is by far and away, at $1.75 billion in construction, the biggest development the city has ever seen, perhaps the biggest the nation has ever seen," Premier Daniel Andrews said.

Mr Andrews said planning approval had been granted in less than 12 months.

"In other parts of the country similar planning approvals, even much smaller projects, take years and years," he said.

"This process has been careful, it's been considered, it's involved the department, the city council, the state architect."

Two new cafes will be built at Queensbridge Square and the area will be landscaped. ( Supplied: Victorian Government )

Former railway bridge to be re-styled to resemble NYC high line

Mr Andrews said the project would also include upgrades to the area, including landscaping and two new cafes at nearby Queensbridge.

He said another $15 million would be spent improving Sandbridge Rail Bridge to be "reimagined, much like a Chelsea high line in the great city of New York".

An artist's impression of a bridge over Queensbridge Square as part of the development. ( Supplied: Victorian Government )

Other planned upgrades include landscaping on Southbank Boulevard, a new bike strip, street furniture and more trees along Queensbridge Street.

"[The] site could be so much better in a city that needs more hotel rooms, given the blockbuster major events calendar we have," Mr Andrews said.

He said the project would create jobs for the state.

"What we're really approving is 4,000 jobs ... for construction workers and for those in the hospitality sector, in the construction phase and for the future.

"That of course adds to the ten-and-a-half thousand jobs that Crown currently support."

The building, to be developed by Crown and the Schiavello Group, has been designed by firm WilkinsonEyre after it won an international design competition.