By Sarah Spina-Matthews in Sydney

After almost 15 years in the works, a construction marvel officials hope will become a region’s cultural backbone will finally open its doors. 

The billion-dollar Powerhouse Parramatta will open to the public on Saturday, with five free exhibitions and a sold-out program for more than 20,000 visitors across its launch weekend.

Speaking at a preview event for the opening of Sydney’s biggest cultural project since the Opera House, interim chief executive Abbie Galvin said the venue would be a place of innovation, learning and wonderment.

“It will be the cultural backbone for Western Sydney,” she told reporters, standing in front of a massive art installation poised against the building’s dazzling glass and steel exterior.

The celebrations were marred by an air of controversy, with Ms Galvin parachuted in as the new face of the project in place of the museum’s veteran champion Lisa Havilah.

Ms Havilah stood aside in late August after seven years at its helm while allegations over poor governance and procurement practices were investigated.

Arts Minister John Graham said the project delivered on people’s desire to have easier access to arts and culture.

“It is the first cultural institution for the west … this is where the cultural energy is in Sydney,” he told reporters on Friday.

Access to 65 per cent of the performances, talks, parties, screenings and workshops across the 23-day opening program would be free, he said.

The First Nations-led exhibition Overflow, a collaboration between communities across NSW and filmmaker Ivan Sen, is on the building’s top floor.

It centres around a pool of water that visitors can take off their shoes and wade into, which rises and falls to reflect the river below it.

“We’ve made a really radical departure from normal museum exhibitions where you see objects,” Powerhouse Parramatta’s director of First Nations Beau James said.

“The objects in this space are the communities we’ve worked with.”

From Saturday, visitors will also be able to see the first Australian exhibition by world-renowned British artist Es Devlin.

Ms Devlin – who has collaborated with artists including Beyoncé, Adele and Lorde – said she had been visiting Parramatta from her home in London for three years to develop her show The Turning.

It begins with an immersive video piece, which ends as the screen splits in two and opens into a two-storey labyrinthine space covered entirely in mirrors.

“I’ve worked all around the world, and I haven’t been part of something this momentous,” she said.

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