The debut of the film Pig Iron Bob was a resounding success on Saturday night, with the Wollongong Town Hall packed with 800 people.

The film, directed and produced by Sandra Pires of Why Documentaries, tells the story of how Port Kembla wharfies stopped loading Australian pig iron on the Dalfram ship, which was headed for Japan in November 1938.

The workers believed the pig iron would be used by Japan in the invasion of China, where thousands had already been killed. Their actions sparked a nine-week stand-off with the Australian government and prompted the then attorney-general and future prime minister, Robert Menzies, to visit Wollongong to end the dispute.

Ms Pires said the film, which was largely shot around the Port Kembla area yet spanned continents, was given a standing ovation by the audience.

"I was overwhelmed by that response," she said of the film which has a strong peace message.

Ms Pires said people were moved by the appearance of Mr Menzies' daughter Heather Henderson and Suzanne Roach, daughter of the late Waterside Workers Federation South Coast secretary Ted Roach, who stood together on stage.

"I think that was a really powerful moment for a lot of people in the audience," she said.

"Heather Henderson came to the town only a short distance from where her father had been given the nickname (Pig Iron Bob) 77 years earlier and that was an impressive moment that a lot of people in the audience took away with them."

Emotions were also stirred when several members from the Nanjing orchestra performed on stage. The film includes interviews with the survivors of the 1937 Nanjing massacre in China.

The film will screen at the Gala Cinema in Warrawong on March 28 at 6pm.