The National Trust has objected to revised plans for a casino-resort at Barangaroo south as "contemptuous" of planning and conservation principles and "usurping" public space without public benefit.

The Trust, a long-time critic of the $1.5 billion Crown Resorts plan, was responding to the latest modification to plans for the Barangaroo casino-resort, currently under review by the state government.

An artist's impression of Crown Resorts' proposed casino, hotel, apartment building at Barangaroo Credit:Wilkinson Eyre Architects

"The Barangaroo planning process … is contemptuous of the principles of orderly planning and heritage conservation," the submission, signed by the Trust CEO Brian Scarsbrick, reads. "Sydney deserves better than this."

The comments follow a near-doubling in size of the development, revealed last year to some controversy.