At a cost of $498 million and to be completed over nine years, the ambitious redevelopment has received the backing of both major parties.
Revealing the master plans on Thursday, memorial director Brendan Nelson said recent veterans and current soldiers would be given the space and recognition they deserve.
The war memorial's emphasis on recent conflicts follows the success of the Invictus Games, an initiative of Prince Harry to put wounded, injured and sick armed services personnel on centre stage.
Prime Minister Scott Morrison said the overhaul of the Canberra institution, expected to be completed by 2028, would bump up visitor space by 83 per cent.
"The Australian War Memorial will be able to display more of their collection and proudly tell the stories from recent years in Afghanistan, Iraq, the Solomon Islands and East Timor," Mr Morrison said.
Visitors will be able to watch unclassified live feeds of current defence activities and soldiers at work.
But in a move that has angered some historians and architects, the iconic Anzac Hall will be knocked down and rebuilt despite only being opened in 2001 at a cost of $17 million.
"Bringing in the bulldozers to destroy such an investment - of effort, of culture and at the end of the day, taxpayer dollars - is a colossal waste and mark of disrespect," Ms Cousins said.
Dr Nelson has backed the expansion, saying the galleries are at capacity and needed to grow.
"The memorial's ability to tell the stories of those men and women who serve in Australia's defence forces has now reached its limits," Dr Nelson said.
Unveiling of the plans at Parliament House saw veterans, past and present, tell their stories and what the memorial means to defence personnel.
Ben Roberts-Smith, who has taken Fairfax Media to court over reporting of his professional and personal life, was one of the former soldiers interviewed during the ceremony.