The planned expansion, estimated to cost about $500 million, would include tearing down the existing ANZAC Hall to build a larger facility that would host more of the memorial's collection. It also proposes the building of a new glazed link and the expansion of the C.E.W. Bean Research Centre among other minor works.

The federal government's own advisor, the Australian Heritage Council, said it couldn't support the major redevelopment of the memorial.

The council's chairman, former Liberal minister David Kemp, slammed the proposals in a July submission to the development's second public consultation.

Dr Kemp wrote the intent to expand the memorial was commendable but that the heritage impact assessments had not adequately addressed alternative options that would avoid the loss of heritage value.

The loss of the surrounding natural areas to the expansion, Dr Kemp added, would also be detrimental to the site's overall aesthetic.

"Physical expansion to support the display of large objects such as submarines and aircraft is not a sustainable intent over the long term and, in the current circumstances, cannot be achieved without significantly impacting listed heritage values," Dr Kemp wrote in the submission.

"Regrettably the council cannot support the conclusion that the proposed redevelopment will not have a serious impact on the listed heritage values of the site and recommends that the matters above be given serious attention."

READ MORE:

But a heritage impact statement, conducted by Sydney heritage architecture firm Hector Abrahams Architects and released in late September, found while the plans were controversial, it would positively impact the popular memorial.

"The loss of the existing ANZAC Hall is a sole significant loss of value and has a substantial negative impact on the heritage significance of the place. We understand this is controversial," the impact statement read.

"In view of the duty of the memorial to develop commemoration, and since the perhaps superior values of historical processes are conserved, this is reasonable."

It recommends moving ahead with the hall's demolition, which will additionally rectify some issues regarding the roof's visibility and aesthetics from Mount Ainslie.

"The demolition of ANZAC Hall is the most detrimental aspect of the proposal, representing the loss of fabric of aesthetic significance," the impact statement read.

"Despite the high impact of the demolition of ANZAC Hall on the aesthetic values of the place, the proposed development contributes positively to the social, research and rarity values of the place."

The final preliminary documentation is now under consideration by the Department of Agriculture, Water and the Environment.