It was an act of bravery worthy of place in Australian folklore.

Now, 70 years after the bloody Wau-Salamaua campaign fought in Papua New Guinea during World War II, historians are calling for the military's highest honour, the Victoria Cross, to be posthumously bestowed on Australian war hero Leslie "Bull" Allen.

On July 30, 1943, during an American assault against the Japanese on Mount Tambu, more than 50 US soldiers were injured. Two medics were killed trying to retrieve them.

The Australians were not supposed to be involved in the fighting, but having witnessed so many casualties, Allen, a stretcher-bearer, was determined to do what he could.

A Ballarat filmmaker who researched Allen's story, Lucinda Horrocks, says what the soldier did next was extraordinary.

"So this is the point at which Bull decides to go up and start carrying men out one at a time over his shoulder, through this terrain, facing the snipers and the machine gun fire and the mortar fire," she said.

Amateur historian David Cranage says each time he went back for another rescue attempt, soldiers would make bets on whether he would return.

"Backwards and forwards, backwards and forwards. Magnificent courage, unbelievable," he said.

"I've never heard anything like it before in my life and I've spent many years studying military history.

"Remember, he was carrying men from another country.

"His heart was so big. He just hopped in. It wouldn't matter where you came from. That's the mark of the man."

Historical records show Allen saved at least 12 men that day, but witnesses have told Allen's children that their father saved 18 American soldiers.

His son, Les Allen, says his father did not boast about what he had done.

"It is emotional because he didn't talk about it all that much," he said.

"I found out a lot of these things that he did through other people, because the main thing is that he was my dad and he was a damn good dad."

In the United States he was hailed a hero. Bull Allen was awarded a Silver Star, the highest honour possible for a non-American.

First lady Eleanor Roosevelt was one of many to write him a letter of gratitude.

She continued to keep in touch over the years, even sending him a note of congratulations when he was engaged to be married.

Bull Allen later named his only daughter Eleanor.

Such was the American admiration for the Australian, he was even offered Hollywood film roles, but he turned them down.

In 1944, after a series of emotionally volatile incidents, Allen was assessed as "unstable" and discharged.

Suffering severe post traumatic stress, he lost the power of speech for six months.

During this time the Australian Army sent him a Military Medal, but it was for an act of gallantry in an earlier battle.

A canteen at Puckapunyal was named in his honour, the first time any part of an Army base was named after a soldier who had not won a Victoria Cross.

His actions on Mount Tambu were never widely recognised.

Bull Allen died in 1982.

"He should have been awarded the Victoria Cross many times on that day on Mount Tambu with what he did," Mr Cranage said.

"He put his life on the line."

Mr Cranage hopes that a statue will one day be erected in Bull Allen's home town, Ballarat.

Ms Horrocks says it is her hope that Australians recognise the man in the photograph carrying an American soldier.

"I would like Australians to be able to put a name to that beautiful, iconic photograph and say that's Bull Allen and he was an extraordinary Australian."