"There are about 332,000 pages of material and it corresponds to about 22,000 individual patrol reports so it's quite a large set," she said.

Ms Creely said the reports mostly covered the period between the end of World War II and PNG's independence from Australia in 1975.

"That's a period of time when there was tremendous change in PNG," she said.

"If you're looking at reports from the highlands, there are reports that are for first contact situations where Europeans had not gone before.

"All the way to places along the coast where there had been mines and plantations and all kinds of Western development for decades and decades."

The duties of patrol officers were many — they were administrators, census takers, policemen, magistrates and gaolers. Some were required to go on arduous patrols into unexplored territory.

At times it was dangerous work, like when Bill Brown and his patrol came under attack while investigating two murders in the eastern highlands.

"[We were] very close to being pin cushions. Arrows were flying high up into the air and coming down vertically," he said.

"I fired two warning shots. That didn't do any good. My lance corporal shot one of the attackers who was killed instantly."

Mr Brown was among thousands of young Australian men who went looking for adventure as a patrol officer. His first posting was to Yule Island north-west of Port Moresby in 1950.

Over the next 26 years he worked right across the territory, from the rugged highlands to the Sepik in the west and Bougainville in the far east.

"I was snared by the country and the people," Mr Brown said.

"I was being paid to do something most people would've given fortunes to experience. I wasn't getting paid very much but it was a lovely life."

As one academic has noted, the patrol officers and their reports were "the sole sources of information for successive administrations ... with regard to villages, their numbers, hopes, fears and reactions to changes".

Of the thousands of reports, one that sticks in Ms Creely's mind contains the first recorded observation of the disease kuru, a brain-wasting condition similar to mad cow disease.

The disease affected the Fore people of PNG's highlands and was caused by the consumption of human brains during funeral rights.

"I was asked by someone who was writing a history of the research on kuru to find that mention, and it was a mention of a patrol officer who said he came across a little girl sitting beside a trail and she was shivering uncontrollably, so to me that was really a poignant picture," Ms Creely said.

Despite the incredible exploits of the patrol officers, their stories are not widely known in Australia, and nor is the story of Australia's colonial history in PNG.

Laurie Bragg is another former patrol officer who is drawing upon his own reports and the reports of others to write a history of PNG's Sepik region.

He hopes that now they are available online there will be renewed interest in the period among historians and the general public.

"I have heard it said, and probably very arguable that it was the only colonial exercise where the colonial power put more into the country than they took out of it," Mr Bragg said.

"I think it's a proud piece of Australian history and we just don't know about it."

Read Bill Brown’s A Kiap’s Chronicle, being serialised in PNG Attitude