Appearing on ABC radio on Tuesday, Ms Berejiklian reaffirmed the NSW government's commitment to "a Powerhouse museum" in Parramatta, but said all options were on the table as the government considered the business case for the move.

"I don't know if I've said this publicly but I'm looking at the costings to see how we can deliver this in the best way and to see what opportunities exist," Ms Berejiklian said.

Asked if this meant the government might build a second Powerhouse museum, Ms Berejiklian said: "I'm just saying we're looking at opportunities but I want to say straight away that western Sydney is going to get a cultural institution, a Powerhouse museum, but I'm looking at all the options."

The government announced in 2014 that the Powerhouse museum would move from Ultimo to Parramatta, following several years of declining crowds and a major redundancy program, but opponents have claimed it would be better to invest in the current heritage site and move some of the collections to a satellite in the west.

A proposed site has been found on the banks of the Parramatta River and western Sydney leaders want it to be housed in an iconic building that would draw visitors from around the state.

The plan is now the subject of a parliamentary inquiry, which is investigating plans to sell off the Ultimo site of the Powerhouse as part of a broader examination of museums and galleries.

Former Powerhouse director Lindsay Sharpe has put the cost of the relocation as high as $2 billion, which would be 10 times the estimated sale price of the current site.

This figure was ridiculed by Parramatta Council's interim general manager Greg Dyer in a speech to the Property Council last week, who claimed that opponents of the move were peddling misinformation.

"Melbourne built a new museum - and relocated 16 million artefacts and specimens from its CBD - for less than $450 million in today's terms," Mr Dyer said.

"So for $2 billion you could build three museums and still have plenty of change."

But Ms Berejiklian said the government was not doing it for financial reasons.

"Western Sydney is the fastest growing part of Sydney and it's appropriate for them to have a cultural institution," she said.

Some observers believe the government is backing away from moving the Powerhouse in its entirety, raising fears in western Sydney, which is relying on the museum to lift its cultural profile.

Parramatta Council released a cultural plan on Sunday that described the relocation of the Powerhouse as "a catalyst for increased opportunities and enhanced arts and culture".

Western Sydney Business Chamber director David Borger said it would be a challenge for the government to run two operational budgets, especially given the Ultimo site needed significant rehabilitation.

Parramatta had been named in the State Infrastructure Strategy as the second cultural precinct of NSW, Mr Borger said. "The linchpin to that is the Powerhouse."

Arts Minister Don Harwin was asked in the upper house in February whether the government was considering a backflip on the decision.

He replied: "Once the final business case has been received it will be looked at by me and considered by cabinet and a final decision will be made."