Mary Bielski discovers remnants of a forgotten WW2 camp site for conscientious objectors on her property near Shannon.

Amateur historians have begun to uncover the "forgotten" history of two Shannon prisons, where 250 conscientious objectors were detained during the Second World War.

In 2012, Shannon farm owner Mary Bielski began finding remnants of barbed wire, copper pipe and concrete foundations sticking out of her paddocks.

Through piecing together bits and pieces of information she learned the ruins were the remains of Whitaunui camp, one of two nearby sites that were among New Zealand's largest camps to house men who refused compulsory military conscription.

Warwick Smith/ Fairfax NZ. Mary Bielski with dog Lass, on her Shannon farm, where she has been uncovering a political prison work camp for conscientious objectors during WWII.

Finding little official information about the camps, she continued to research, joined by friend Margeret Tate. They tracked down mentions in books, letters, obscure publications and pre-recorded oral histories to learn more about both Whitaunui and Paiaka camps, and have begun excavating and recording the physical remnants.

Bielski estimates the camp covered about 20 acres of boggy land near the Manawatu River. It had a hospital, kitchens, toilet block, gardens and a grid of 'public works' huts for the men to sleep in, that formed a grid next to the space her house is now on.

On Sunday Tate delivered a talk about the project at Te Takere in Levin.

Warwick Smith/ Fairfax NZ. A historical photo believed to have been taken of prisoners in front of 'public works huts' that housed them, at the Whitaunui camp, during WWII.

"It is a part of local history and it has been very largely forgotten, and there are sites here that have now been identified and can be found.

"Most people despised conscientious objectors, there was a very strong feeling against them, and they were ostracised for a considerable time after they left the camps," she said.

Both camps operated from 1941 until 1946, and housed men aged from 18 to 40, from throughout the country. They appeared to have been kept in good physical health, fed well (especially with vegetables they grew), and inmates did the cooking.

The huts were probably cold, and furnished sparsely with one or two beds, and perhaps a table and chairs.

"They worked weeding flax. There were very large stands of flax, with various kinds of weeks growing, especially blackberry, and they spent their time cutting down those weeds.

"I don't know that it was particularly hard, but it was very boring indeed.

"There were constant objections, mainly that it was no use at all - and some of the people that were in charge of them thought it was a waste of time too."

Some library books were allowed, letters were controlled, few visitors were allowed, and prisoners were often moved between camps arbitrarily.

"It made an enormous impact on them, there was quite a lot of people that were very depressed.

"It was very difficult for the wives, because the men weren't ... sending them any money, and a number who tried to get work found it hard.

"When people found they were married to a conscientious objector there could be enough nastiness that they felt they needed to leave."

There were some "spectacular" escapes, though escapees risked jail, and more time added to their sentences.

"It's reported a few men once went to a film in Foxton and then climbed back in through the wires," Tate said.

The objectors included pacifists, humanists, agnostics and political objectors. Researchers discovered a surprising number were connected to well-known families, including the brothers of Edmund Hillary and James K Baxter, Dan Long ( later an influential president of the Public Service Association), and some who continued to become university lecturers.

Tate stressed the research project was not intended to make a political statement, but merely to ensure history was not forgotten.

"We are looking into it because it's almost exactly 70 years since they were closed, to the month. They were closed in 1946, and I've found nobody's aware of it.

"Young people are now puzzled about why people were so angry about the conscientious objectors - people have moved on, and can't understand how intense the feelings were."

The research is ongoing, Tate said, but had already resulted in Horowhenua District Council investigating adding the sites to the District Plan and actively seeking more information.