Arthur Chaing was a young man living in Sydney when the Imperial Japanese Army marched on Nanjing, in eastern China, brutally murdering 300,000 civilians and raping 20,000 women in December 1937.

Chaing had fled to Australia to escape the Japanese two years earlier and had settled in to a new life, in a new land.

When news of the atrocities shocked the world, it was the working-class wharfies at Port Kembla who, refusing to load scrap iron on to a ship bound for Japan, embodied the spirit of an ancient Chinese proverb: "Within the boundaries of the four seas, we are all brothers".

The pig iron, as it was also known, was destined to become bombs and steel for the Japanese army to be used against China and some feared, eventually Australia.

The 180 wharfies, led by the militant Ted Roach of the Waterside Workers Federation, refused to load pig iron on to the steamship the Dalfram at Port Kembla's No. 4 Jetty.

For 10 weeks and two days, the wharfies stood their ground with full support of their hungry families.

They received financial support and letters of goodwill from all over Australia.

The working class in Sydney's Chinatown, the market gardeners, greengrocers and barrowmen, would be forever grateful to the wharfies for their sacrifice.

They, too, rallied support with truckloads of fruit and vegetables to help feed the striking men and their families.

"The wharfies taught me a lesson," said Chaing. "To be a real man, to stand up for yourself, to rely on yourself."

Chaing talks of the bond between working-class Chinatown and Port Kembla in a Wollongong-produced documentary titled The Dalfram Dispute 1938: Pig Iron Bob. The film, directed by Sandra Pires of Why Documentaries, will be screened for the first time tonight at the Wollongong Town Hall.

"I first started researching the film in 2011 and was blown away by the story," says Pires. "It was a big deal. These were regular people, struggling people who stopped their labour because they believed it was the right thing to do. I hope that always happens - that people will stand up for what's happening on the other side of the world."

Without the backing of a broadcaster, it took Pires four years to make the film, raising the funds in stages.

"I can't thank our sponsors enough, particularly the Australia-China Economics, Trade, Cultural Association because without them we couldn't have finished the film," she says.

Pires travelled with a film crew to China last year to interview survivors of the Rape of Nanjing. She will return there in September to screen the feature-length film.

"Nanjing was an horrendous chapter in history," says Pires. "At the time there were headlines all over the world."

Some of the footage and stories of the massacre which Pires had obtained from the Nanjing Massacre Memorial Hall were too disturbing to be included in the documentary.

The vision included decapitations, the brutal mass murder of children and the horrendous rape and torture of a pregnant woman.

"The Japanese had been ordered to dehumanise the Chinese and they were treated like cats and dogs," says Pires. "It was a scary time."

Twenty-five of the Japanese perpetrators were later found guilty of war crimes by the International Military Tribunal in 1948, of which seven were sentenced to death and others received life sentences.

However, there has been no formal apology from Japan nor compensation for the victims. China's first state commemoration of the massacre only took place in Nanjing in December last year, 77 years after the genocide.

With relations between the two countries still strained, Pires chose not to include the current political climate in her film.

"It's not part of my story," she says.

"My central theme to the film is peace. The survivors have said they forgive and I think that's a pretty big deal to have captured. It's about peace and moving on. Peace starts at home."

The film entwines a re-enactment of the Dalfram dispute, including the day the then Attorney General and aspiring Prime Minister Robert Menzies came to Wollongong to discuss the gridlock with union officials.

The conservative Menzies refused to back down, it wasn't a matter of right or wrong, he had argued at the time, but that only an elected government could determine policy.

Surrounded by a mob of angry wharfies and their families, Menzies was loaded with a nickname that would stick with him forever - Pig Iron Bob.

The insult was handed to him by the head of the Housewives Association, Gwendoline (Ma) Croft.

"I don't blame Menzies," says Pires.

"He was doing his job, he was seeing it through a legal world. He wanted the ship loaded.

"Japan had been a lifeline to Australia during the depression. They had been our biggest export partner. We've tried to move the story away from Menzies and Pig Iron Bob, which has negative connotations and move it towards the positives.

"We wanted to concentrate on what the families did because that's what should be remembered. This is a multicultural story between China and Port Kembla."

The last surviving wharfie involved in the Dalfram dispute died three years before the filming.

"I'm really proud of the history [of the dispute] and to have been able to capture it before it's gone forever," she says.

In one scene, Menzies, played by Australian actor Bob Baines, is escorted through the angry mob by Ted Roach, played by actor Michael Cormick. Roach was a well-known Communist Party member at the time.

Menzies threatened the wharfies with the Transport Workers' Act, also known to workers as the Dog-Collar Act. The act facilitated a clean path for strikebreakers requiring wharfies to obtain a licence to work. Roach challenged the act and only one licence was ever bought - the one he burned in front of a large crowd. It was a stand reminiscent of the Eureka Stockade.

But heading into the 11th week of the dispute, the wharfies backed down and loaded the ship.

"It had been too long and kids were going hungry," explained Pires.

"Menzies and the union had a verbal agreement that no further pig iron would be loaded after the shipment and that the Transport Workers' Act would be abolished.

"Some may see it as the biggest loss in history, but I'm really proud of [what they achieved]. The wharfies had become empowered. This was an action that for the first time wasn't about pay or conditions. They had done something they thought they could never do."

The Dalfram dispute paved the way for other unions to take on social justice issues.

Pires hopes to recoup some of the production costs through the sale of the DVD and to secure a broadcaster in the coming months.

"This has been my love project," says Pires. "I'm a filmmaker. I want to tell stories that matter. I don't think Australians take ourselves seriously when it comes to our own history."

The Dalfram Dispute 1938: Pig Iron Bob will screen at the Gala Cinema in Warrawong on March 28 at 6pm.