Sydney residents, union, vow to save heritage buildings from being bulldozed for Powerhouse Museum

The construction union has weighed in to the campaign to save two heritage buildings slated for demolition to make way for the new Powerhouse Museum at Parramatta.

CFMEU NSW announced a green ban over the buildings and called on contractors to abide by it.

The move intensifies a campaign to preserve the buildings — Willow Grove, a two-storey heritage villa, and St George's Terrace, a row of modest Victorian period homes.

Darren Greenfield, Secretary of the CFMEU's Construction Branch, has called on NSW Premier Gladys Berejiklian to save the properties.

"These green bans mean no work can be done to destroy these historically significant sites," Mr Greenfield said.

"We hope the Government listens to the people of this community, which are many, that are against the destruction of these buildings.

"We will be here standing in defence of these buildings for whatever it takes into the future."

Suzette Meade from the North Parramatta Resident's Action Group said people would stand firm with the union.

"The Premier should be under no illusion that if a finger is laid on any of these buildings, the community of Parramatta and heritage lovers from all over New South Wales, will put themselves in front of machinery to save them."

Cheryl Bates from the National Trusts Parramatta Branch said environment and heritage impact statements identified the properties at "highly significant" to the Parramatta area, but didn't investigate their adaptive reuse.

The Premier deflected a question about the fate of the buildings earlier today, saying "we've made our position on that clear from the beginning".

Last February Ms Berejiklian told Parliament that "…we asked every single person who bid for the project to put forward a proposal that protected that heritage house.

"Unfortunately, that was not able to occur."