The Australian War Memorial and National Museum have expansion on their minds after this week’s budget announcement.

The War Memorial received $5 million to fund planning of a possible 5,000 sq metre exhibition space to be located under the landmark's historic forecourt.

Acting director Tim Sullivan said plans so far were designed to better use existing areas, and create new Afghanistan and Iraq war galleries to showcase military equipment including a Chinook, a Seahawk and two F/A18s.

The expansion - expected to be developed over the course of several years – should also include enhanced visitor amenities, facilities for school visits and new reflection areas.

“Everyone should be assured there will be minimal impact on the external presentation of the memorial. The heritage building will not be changed in its exterior perspective,” Mr Sullivan said.

“We're looking to get the first pass business case done as soon as we can, with the second business case to include a fully fledged concept with costings and documentation ready to go to tender for construction.”

The National Museum of Australia has been granted $2.29 million of extra budget funding over three years.

“That's important because it will allow us to take forward programs and opportunities for the public that would otherwise be impossible,” Dr Trinca said.

The museum will also get $8.9 million over three years from a previously-announced modernisation fund to combine ‘backroom’ services with Canberra's other national institutions.

“We get both the material benefit of working together but we get also a cultural benefit from being closely aligned on these corporate functions that allows us to focus on our public services,” Dr Trinca said.

The National Gallery of Australia has welcomed a four-year funding allocation of $1.887 million, while the National Portrait Gallery received nearly $700,000 in additional funding over three years through the Public Service Modernisation Fund as well.