The Western Australian Government appears set to try to cut costs on the long-promised new WA Museum in the heart of the city.

The previous Liberal-National government promised the public a new $428-million museum to replace and upgrade the current facility at the Perth Cultural Centre.

But the ABC has been told that as the McGowan Government looks for ways to find savings in tight financial times, the project's budget could be cut by as much as $40 million.

Asked about whether it was revisiting the project's budget and specifically about it being reduced by $40 million, the Government did not deny the claim.

In response to questions from the ABC, the Treasurer's office released a short statement saying the McGowan Government was "fully committed to delivering a world-class museum that represents value for money for all West Australians".

"A budget allocation for the project is on the public record in previous budget papers," a spokesman for Treasurer Ben Wyatt said.

"Currently the Government is in the process of negotiating final design and costings for the project that will meet the public's expectations on all criteria associated with its development.

"We will make an announcement in due course."

Earlier this year Mark McGowan said the project was expected to create 3,300 jobs during the construction phase. ( Supplied: WA Government )

Government remains tight-lipped on construction contract

The previous Government allocated $378.5 million over the next four years in last year's budget to deliver the project.

In July last year, the Barnett government announced it had awarded the Brookfield Multiplex team the contract to design and construct the new museum.

At the time of revealing the design, then-premier Colin Barnett described the project as "very affordable", despite the state's record debt and deficit levels.

The Treasurer's office remained tight-lipped on what the contract struck between the Brookfield Multiplex team and the previous government was worth, whether it would need to be renegotiated and whether any change in scope to the project was being considered.

When revealing the design, then-premier Colin Barnett described the project as "very affordable". ( AAP: Richard Wainwright )

In May, Premier Mark McGowan and Culture and Arts Minister David Templeman turned the first sod of soil at the site as demolition works got underway on the non-heritage parts of the existing buildings.

At the time, Mr McGowan said the project was expected to create 3,300 jobs during the construction phase, with 1,800 being in the construction sector.

Under the previous government's plans, the redevelopment links the existing WA Museum heritage building to a much larger, overarching modern structure, with a wide open public plaza in the centre.

The museum was designed to be almost four times bigger than its predecessor, with nearly 7,000 square metres of galleries, including a single 1,000sqm space for "blockbuster exhibitions".

An artist's impression of the new museum. ( Supplied: WA Government )

The design includes education studios, view areas and retail outlets, while the exterior of the entire top floor will be used as a vast screen to project images such as Aboriginal art or West Australian landscapes.

The WA Museum closed its doors to the public in June last year for four years to enable the redevelopment.

The Treasurer's spokesman said work on the site, including the non-heritage demolition, continued.

"Earthworks, grout injection and piling commencement is imminent," he said.

The new museum is scheduled to open in 2020.