A hit with generations of children and their parents since the 1920s, when they first went on show in Melbourne,.

the models have received little or no cleaning or conservation since they were moved into their current positions in the early 1970s.

AWM acting director Nola Anderson said, while in the tradition of massive battlefield canvases depicting actions such as the battles of Waterloo and Trafalgar, Australia's dioramas had no direct predecessors. ''They were not like anything that had ever been done before,'' she said.

The money for the redevelopment was pledged by the Prime Minister earlier this year and, while it has yet to be approved by the Public Works Committee, Ms Anderson is confident it will get the green light. ''We [the AWM] have a good track record with these types of projects,'' she said.

Created by sculptors and artists who toured the battlefields in 1919 and worked with military experts to ensure historical accuracy, the dioramas recreate in miniature key scenes from the ''war to end all wars''.

They will be an integral part of the redeveloped First World War Gallery and, for the first time, are to be arranged in chronological order.

But the gallery is to be closed from mid-2014 until early 2015 while the work takes place.

Alana Treasure, a conservator and one of the AWM artisans charged with refurbishing the eight large dioramas and two sets of small ones, said the work was painstaking. The emphasis was on preservation, not restoration. ''We will not be overpainting anything,'' Ms Treasure said. ''But we will repair visible damage.''

When the dioramas, which featured backdrops painted by Louis McCubbin, the son of Frederick McCubbin, were relocated 40 years ago, a less restrained approach prevailed. Many of the figures were overpainted at that time; model figures missing parts had them replaced with less than appropriate ''replicas''.

The human figures, crafted to different scales to provide the right perspective in the landscapes, are modelled from lead and pewter. Plaster of Paris, augmented with lathes, chicken wire and horsehair, was used to make the landscapes.

Ms Anderson said while the dioramas were now seen as a very old-fashioned way of telling the Anzac story, they had been state-of-the-art at the time - and could work well in the 21st century with the addition of modern technological assists in the form of interactive wifi technology that would allow viewers to access narrations that bring the scenes to life.

Even without that facility, the large dioramas are a powerful medium. The panoramic depiction of the final Australian assault on Mont St Quentin on September 2, 1918, is a case in point.

Diggers are clambering up out of hurriedly dug trenches; one small group mans a Lewis gun in a machinegun nest to cover the attack, a wounded digger lies in the bottom of the trench and a dead German is nearby. It is a serene summer's day with less than 40 per cent cloud cover and in the valley below a river meanders through fields and forests.

Could any of the men fighting there that day have even dared to hope that the end of the war was a little more than two months away?