A hunt is underway for the living relatives of Australian soldiers who left their mark in a cave just kilometres from the bloody warzone of the Western Front.

For members of the Australian Imperial Forces (AIF) stationed on the battlefields of the Somme during World War I, visits to tourist attractions like the caves at Naours, in France, formed part of their rest and recreation activities.

Just a few years ago, an archaeologist researching the caves, Gilles Prilaux, found a chamber containing 3,200 wartime inscriptions scrawled on the cave's walls, including nearly 2,000 attributed to Australians.

Almost immediately, a search to find the soldiers and their stories commenced, to add to Allied war history records maintained on the former battlefields.

Mr Prilaux has a record of the graffiti with all the entries photographed, recorded, and inventoried.

Australian soldiers like these, posted in France, visited the caves for some R and R. ( Supplied: AWM C00450 )

"This discovery is very important because it addresses a subject rarely discussed: recreation during the war," he said.

"These soldiers came to visit the underground of Naours during periods of rest or convalescence [and they] left their names in a peaceful moment, they forgot for a moment the horror of the battlefield."

In the future, Mr Prilaux hopes to publish a follow-up to his book Silent Soldiers of Naours, which covered the first 50 soldiers identified.

Barber searches for stories

Mr Prilaux has been assisted in piecing together the puzzle of the soldiers' stories by a number of amateur Australian war historians.

One researcher is Townville barber Elaine 'Mouse' Fountaine, who has been hunting for clues through online databases and phonebooks to find soldiers' living relatives.

"It caught my interest so I started investigating, then I contacted Gilles over in France, emailed him and I've been conversing ever since and finding other descendants for him," Ms Fountaine said.

"I've found 14 family descendants so far, and am confirming a few others which is a feat in itself.

"A lot of people don't realise some of their family members served in World War I.

"Some didn't know much about it, some died over there, and some came back with problems, but everyone's proud of their military heritage."

Missing soldier's signature and family found

One relative of a soldier who left his mark on the caves is Gary Clegg from Lucinda, just 100 kilometres north from where his grandfather's cousin, Alfred Henry Clegg, was raised in Townsville.

Harry Clegg, as he was known, was a reservist who joined the AIF in 1915, serving at Gallipoli and in France as a sergeant in the 26th Infantry Battalion.

The 22-year-old was presumed killed in action at the Battle of Pozieres on July 29, 1916.

Alfred Henry Clegg's family plan to return to France to see his signature in the caves. ( Supplied: Gilles Prilaux )

Gary Clegg was contacted by Ms Fountaine, who informed him that his grandfather's cousin was one of the soldiers whose signature was found on the Naours cave wall.

"It's a fitting legacy for people like Alfred Henry who were missing in action, their bodies never recovered," he said.

"At least they have some recognition, some monument to their service and to their bravery."

Around 11,000 Australian soldiers' bodies were never recovered during WWI, many resting in unmarked mass graves hastily dug following battles.

Hunt continues

While Mr Clegg has provided information about his relative, only 495 biographies of the nearly 2,000 names have been completed.

Known by various aliases, Donald Herbert Auld MacGregor enlisted at the age of 15 in late 1914. ( Supplied: National Archives of Australia )

Ms Fountaine said the passage of time, along with scant or falsified war records, had made progress difficult.

"One enlisted underage. His name was Sergeant Herbert Evans but he also went under the name of Herbert Francis Auld," she said.

"His real name was Donald Herbert Auld MacGregor; he was born in Ipswich but later lived on the Gold Coast."

With at least three aliases after enlisting in 1914 at the age of 15, MacGregor was awarded the Military Medal for bravery as a 17 year-old when a lance-corporal with the 15th Battalion.

He survived the war and married at least twice so finding MacGregor's descendants has been difficult for Ms Fountaine who is calling on the public's help to track down more of the soldiers.

"I found him on the electoral roll living at Mermaid Beach in 1967," she said.

"He's a very mysterious person ... I tell you what, he's very elusive."

Archaeologist Gilles Prilaux can be contacted via email at gprilaux@somme.fr by any family members of soldiers who were in the Somme region during the war, who would like to check if their relative's name is inside the cave.