A 100-year-old mystery involving an Australian soldier and a little-known battle in Russia could soon be solved.

Key points: Sergeant Sam Pearse was killed in combat in Russia in 1919, a year after World War I ended

Sergeant Sam Pearse was killed in combat in Russia in 1919, a year after World War I ended Australia's involvement in the Russian Civil War is still largely unrecognised

Australia's involvement in the Russian Civil War is still largely unrecognised Russian and British governments are in sensitive negotiations to repatriate fallen soldiers

Victoria Cross recipient Sergeant Sam Pearse was killed while fighting against the Soviet Red Army in 1919. After the battle, the location of his grave was lost.

But now his remains may finally have been found south of the Russian city of Archangel, on the icy shores of the White Sea in Russia's arctic north.

His grandson, Richard Christen, has embarked on a journey halfway across the world in the hope of bringing Sergeant Pearse's remains home to Australia.

"I thought if I ever got the opportunity I'd like to go, I'd like to see where Sam died, where he was buried," Mr Christen told 7.30.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 46 seconds 46 s (WARNING: Video contains images of human remains.) The likely remains of Australian soldier Sergeant Sam Pearse are removed from the ground.

"We never thought his grave would be found."

Lost in the fog of war

Sergeant Pearse's death in combat, a year after the conclusion of World War I, marks an obscure footnote in Australian military history.

After surviving the horrors of Gallipoli and the Western Front, he was one of 120 Australians who volunteered to fight the Bolsheviks in the Russian Civil War.

Relief Force for Russia recruitment notice ( Supplied )

Australian military historian Damien Wright, who travelled with Mr Christen to Archangel, has been researching this forgotten odyssey for 20 years.

"A band of amateur battlefield archaeologists have been looking for Sam's grave for at least 10 years," Mr Wright told 7.30.

"The location where the grave was eventually found was in an old scrapyard beneath timber and debris."

The historic battleground where Sergeant Pearse and his fellow diggers fought the fledgling Red Army is about four-and-a-half hours south of Archangel.

It was there, at first light on August 29, 1919, that Sergeant Pearse earned his posthumous Victoria Cross, when he charged a bunker of Red Army soldiers before being cut down by machine gun fire.

"I think he thought [the Russian Relief Force] would be nothing — a bit of a picnic — after what he'd been through in World War I," Mr Christen said.

A long way from Mildura

A box containing the likely remains of Sergeant Sam Pearse is viewed by grandson Richard Christen and historian Damien Wright. ( Supplied )

Mr Christen believes the remains they have discovered are his grandfather's.

"[I'm] 99.9 per cent certain, because the remains of the slouch hat were with him and he had one toe missing on his right foot," he said.

"Sam's Australian service record confirmed that the middle toe of the right foot had been amputated before he'd sailed for north Russia," Mr Wright added.

Mr Christen is waiting on DNA testing to confirm his search is finally over.

The original gravesite of Sgt Sam Pearse in Archangel, Russia. ( Supplied: Richard Christen )

What happens to the remains are subject to sensitive negotiations between the Russian and UK governments — the bones were found in what was originally a British war grave — but Mr Christen hopes his grandfather can finally be laid to rest on Australian soil.

"In an ideal world I'd like to see Sam's remains brought back to Mildura where his statue stands at the war memorial," he said.

"To the best of my knowledge the Australian Government has not been the least bit helpful, but there's not a lot the Australian Government can do."

The Department of Veterans' Affairs said the Government "recognises the remarkable service offered by Sergeant Pearse VC", but that enquiries regarding the grave should be directed to the UK Ministry of Defence.

7.30 has approached the UK Government for comment.

While a memorial for Sergeant Pearse and other fallen soldiers stands in Archangel, Mr Wright hopes that the life, death and bravery of his grandfather and other Australians who served with him are not lost over time.

"We should know more about it, so we can give them the recognition and the commemoration they deserve," he said.