Already under investigation by the Fair Work Ombudsman, Australia's largest poultry manufacturer, Baiada, has now been cited by WorkSafe Victoria over the death of a contract worker at one of its plants.

In August this year Sarel Singh, 34, died instantly when fast moving machinery he was cleaning decapitated him.

A preliminary report on the workplace death, obtained by Lateline, has found Baiada breached occupational health and safety laws by not controlling the risks at the plant.

Six weeks ago, Lateline revealed how Baiada poultry was under investigation over claims of unlawful and unethical treatment of its majority migrant workforce.

Tim Kennedy from the National Union of Workers is horrified by the incident.

"It is absolutely horrific in a civilised society that we have now the fact that these things still occur, it is just not acceptable," he said.

Four years ago, Sarel Singh risked everything to find his fortune in Australia.

His brother, Harry Singh, says Sarel took out a large bank loan in his home state of Punjab to fund the relocation.

"Yes he was excited at that time. He was looking for a job - he can't get it here. Then he tried to get to Australia and have some study over there afterwards and have a job over there, for a better life," he said.

After graduating, Sarel worked as a taxi driver before getting married.

He then joined the Ecowize company, which has a contract to clean the production areas of the Baiada poultry processing plant in Melbourne's west.

"He used to say that life working at that place was like a hell. It's a very hard job and he was tired of that job. But due to the burden of the loans and debts over here and in Australia too, he had to work over there and he was struggling hard," Harry Singh said.

However, Sarel Singh was ready to give up and go back to India. But on August 12 he was killed at work.

Sarel had actually finished his four-hour shift when he was told to go back and re-clean the pack line area.

Mr Kennedy from the National Union of Workers says Sarel was not familiar with the line.

"Now the line he went to was not a line that he normally cleaned. He did not have his full protection gear on in terms of glasses and helmet," he said.

According to the union, as Sarel was standing on a ladder hosing down the line, his jacket was hooked. He was swept into the next machine and decapitated.

The union says the chain line should be stopped while it is cleaned.

"Over time what has happened is the company, to maintain production, to maintain the returns they want to get, has pushed the risk to workers by speeding that chain up so they have run the chain 20 to 40 birds per minute and people have been asked to clean it," Mr Kennedy said.

"The night on which Mr Singh was killed the chain was running at absolute capacity ... 180 birds per minute."

Harry Singh cannot believe that he has lost his brother.

"How can I believe it? My brother, he was my real brother and only brother. I have no brothers else ... and just a great shock to me," he said.

"My mother is feeling shock. Very upset with this because she has lost her older son. She has gone, gone through lot of things throughout [her] life and sacrificed a lot. Sacrificed the pension on his loans. So tough life for her now."

WorkSafe Victoria was soon at the scene of Sarel Singh's death.

Its report, obtained by Lateline, found that the production line posed an injury risk.

It also confirmed the line was operating at the top speed of 183 birds per minute, and that "by not adequately controlling the risks associated with this plant [Baiada poultry] is in contravention of the requirements of section 21(1) and 21(2)(A) of the occupational health and safety act."

Baiada poultry was issued with a prohibition notice, informing the company it must assess and control the risk to workers.

WorkSafe Victoria inspectors returned the next day and found the risk assessment prepared by Baiada was inadequate.

After assuring WorkSafe there would be changes to the production line's power system, the plant was allowed to resume operations.

WorkSafe Victoria has told Lateline the entire meat and poultry industry is now under review.

It says when it comes to work safety, employers should do more than the bare minimum and has reminded employers they are responsible for all employees whether they are staff or on contract.

Lateline has sought comment from both Baiada and Ecowize about Sarel Singh's death.

Both declined an on-camera interview.

Lateline also submitted a series of questions to Baiada about the death and work safety conditions at its plants, but there has been no reply.

The National Union of Workers has more general concerns about the treatment of workers at Baiada, particularly contract workers.

"Baiada is a major poultry processor company - we think that in large part Baiada tend to engage in a way that moves risk from them to people, where risk should not reside in terms of the employer relationship, we think that needs to change," Mr Kennedy said.

Bullying allegations

A separate investigation by the Fair Work Ombudsman into rates of pay and working conditions is still underway after snap inspections at Baiada plants around the nation.

Workers at Baiada's Adelaide plant had complained about being bullied into accepting below-award wages and long hours - often beyond working or student visa conditions.

The National Union of Workers is campaigning to improve safety and working conditions at Baiada's various plants.

Mr Kennedy says management told workers to renounce their union membership this week or they could face reduced hours.

"The workers are expressing great concern, some are in tears, that not only have they been asked to resign from the union, but also being threatened [that] if they don't resign from the union, maybe their hours will change," he said.

"These reports concern us."

But Baiada has rejected the union's allegations.

The company says it has not threatened to cut staff hours or asked workers to resign from the union.

Sarel Singh's family wants answers.

"Yes it should be investigated and if there is a culprit he should be punished as per laws of the Australian Government," Harry Singh said.

The family is also seeking compensation.