About 170 Australian soldiers and more than 200 British soldiers were found in a grave at Pheasant Wood, near Fromelles, earlier this year. They are believed to be the last of the missing casualties from Australia's first and bloodiest engagement in World War I.

Defence Personnel Minister Warren Snowdon made the announcement at Melbourne's Shrine of Remembrance yesterday afternoon on behalf of the Australian and British Governments, bringing delight to those who led the campaign to find the grave.

The exhumation is expected to start in the next northern summer, and Australia will split the cost with the British Government.The French still need to approve the decision, but Mr Snowdon said the relevant minister was ''on the same page''.

Friends of the 15th Brigade member Garrie Hutchinson said the decision was ''wonderful news'' and the culmination of a five-year campaign by researcher Lambis Englezos, who found the grave.

''The casualties suffered in those 24 hours of 1916, 5533, [make it] the single most terrible 24 hours in our nation's history. It's one of the most important events in [our] military history. We need to remember, we need to find them and we need to bury them again with the honour that they all deserve.'' Mr Hutchinson said the condition of the bodies was unknown, and identification might not be possible.

DNA matching was also a costly and time-consuming process.

Mr Snowdon said the Commonwealth War Graves Commission would build a new cemetery near the combat zone and the grave that remained a secret for 92 years. ''It is fitting that these brave men will remain together, close to where they fell, and be buried with the honour and ceremony befitting their incredible heroism and sacrifice,'' he said.

Mr Englezos could not attend the announcement, honouring a prior commitment with descendants of those who fought with the 15th Brigade on the Western Front.

Mr Hutchinson paid tribute to Mr Englezos as the ''hero and leader'' of the search.