A team of 30 archaeologists is to start excavating the grave site in northern France on Tuesday.
The soldiers\' skeletal remains will be reburied - with full military honours - in a new military cemetery next year.
The project has raised hopes that dozens of Australian and British families will finally know what happened to their soldier ancestors who disappeared during the Battle of Fromelles in July 1916.
Australian forces suffered 5,533 casualties during the 24-hour battle - the country\'s heaviest military casualty rate ever recorded - while Britain recorded 1,547 soldiers killed, wounded or missing.
The grave was finally unearthed in May 2008, thanks to years of research by Melbourne schoolteacher and amateur historian Lambis Englezos who pinpointed the exact location alongside Pheasant Wood, on the outskirts of Fromelles.
Families\' identification hopes
It is hoped scientists can extract viable DNA from teeth and bones and match the results with genetic samples from the soldiers\' relatives so as many as possible can be reburied with headstones bearing their names.
Australian officials believe the grave contains about 191 diggers, but they need strong DNA evidence to confirm their identities.
British DNA expert, Dr Peter Jones, who will oversee the DNA tests, expects up to half the soldiers could be identified.
"If we get 50 per cent I would be pretty happy with that," he said. "It\'s quite an exceptional project.
"You are looking at trying to do matches two to three generations back in the past ... to get an answer, which is not something that has been done on any scale for any period of time at all. So it\'s quite unique."
Once the remains are removed from the grave they will be cleaned, x-rayed and photographed before being stored in a temporary mortuary ahead of their reburial at a new military cemetery being built at Fromelles.
DNA samples to be collected
An initial round of DNA samples will be taken from about a dozen skeletons to determine if the genetic material is viable to match with potential relatives.
If it is viable, the Australian and British governments will decide whether to widen the tests.
About 96 Australian families who believe they are related to the diggers in the grave have offered to provide genetic samples.
However in Britain, only a handful of people have come forward so far.
Britain\'s Ministry of Defence (MoD) has written to 350 families it believes could be related to the soldiers and hopes they might offer DNA samples.
"We want to give as many of these people a named grave as we possibly can," said Tracey Vennai, the MOD\'s representative on the Fromelles Management Board.
Search for clues, artefacts
"We will put in the necessary money we need to make sure we track down as many of those families as we can."
The archaeologists will begin excavating the site with a mechanical digger before switching to more delicate hand tools as they uncover human remains.
Consultant forensic archaeologist Roland Wessling said he expected the first remains could be unearthed by Friday.
"But it\'s not just about recovering the bodies," he said.
"We want to learn something. The positioning of the bodies and the artefacts around the bodies will tell us something about what happened here.
"The more we know about what happened here could help identify some of them."
The excavation is expected to run until late September.