The Sydney Opera House is reflected in a harbourside hotel window in The Rocks district of Sydney.

Sydney - The Sydney Opera House, Australia's top tourist attraction, is set to receive a $150-million renovation over the next six years, the state government said.

Changes will be made to the concert hall, the foyer and the entrance, said New South Wales state deputy premier Troy Grant, who unveiled the new working designs.

The state is committed to spend 202 million Australian dollars , Grant said.

Each year, about 8.2 million people visit the Opera House, a Unesco-listed World Heritage site, making it Australia's most-visited landmark.

The renewal will be done in phases, starting in May 2017, Sydney Opera House CEO Louise Herron said Thursday in a press conference in the building's famous concert hall.

The renovations will also include additions to the building, including a creative centre for children, an enlarged public space underneath the iconic steps and a function centre with views of the Sydney Harbour Bridge, Herron said.

The concert hall, the venue's largest performance space seating 2 600 people, will be upgraded with new acoustics, said Greg McTaggart, the building director at the Opera House.

“This is not just renovation, but change for a renewed experience,” he told dpa.

“The works will be staged so that the audience and the visitors can continue to visit us and experience the performances,” he said.

The concert hall upgrade will constitute three-fourths of the costs, Herron told dpa, adding it will be closed for 18 months during the renovation, which will start in mid-2019.

“The exterior is iconic, but what goes on inside the building is what brings it to life,” Herron said.

BBM Mueller, a German sound engineering company, was hired to work on the acoustics of the concert hall, architect Peter Bickle said.

“This is not a bad hall, but there are many characteristics that could improve,” Bickle said. “Also, acoustics have moved on from when this place was built, as have the expectations of the audience.”

In addition to the state-funded projects, the Opera House is funding another $34-million project itself to renovate the venue's smaller second theatre.

The renovations will see parts of the Opera House close for different periods of time, “which is a challenge, but we will go as carefully as we can,” Herron said.

“The pain is worth going through ... This is one of the greatest buildings in the world and it deserves that respect and glory,” she said.

The renovation will be the largest upgrade since the site opened in 1973. The Opera House contributes more than 775 million Australian dollars annually to the New South Wales state economy.