At least 130 Bernard Matthews workers are being laid off in the wake of the bird flu outbreak.
The outbreak of bird flu hit the turkey firm's farm in Holton, Suffolk
The Transport and General Workers' Union said employees at Great Witchingham, in Norfolk, would be stood down for 20 days from Tuesday.
The company confirmed the layoffs, but would not confirm any details. It said 500 further staff could be affected.
Meanwhile, Environment Secretary David Miliband told the Commons bird flu was a "continual risk".
He told MPs in a statement that the disease inquiry remained focused on links between Hungary and the Suffolk farm hit by the virus.
Restriction zones would not be lifted before the second week of March, he added.
Earlier, a TGWU spokesman said Bernard Matthews were preparing to lay off a total of 500 workers. He told the BBC the workers were being laid off and not made redundant.
He added that it was crucial for the company to win back the trust of consumers.
The Bernard Matthews spokesman said: "This was a very difficult decision to make but under the current circumstances it was the only option available following the drop in product sales.
"We are also doing everything we can to limit the number of job losses and we are working hard to restore consumer confidence."
Speaking in the Commons, Mr Miliband urged anyone who kept poultry on any scale to observe high levels of biosecurity.
"There can be no guarantee against further outbreaks. In fact the only guarantee is that there is a continual risk," he said.
"That is why it's important that I reiterate my appeal to all poultry keepers to register with the poultry register and to maintain the highest standards of biosecurity."
The environment secretary added that the health risk to workers at the Holton site was "very low indeed", and that consumers were not at risk so long as turkey meat was cooked properly.
Shadow environment minister Peter Ainsworth said there was an "impression" ministers had not had relevant information or known of decisions relating to the trade with Hungary.
He also described reports that testing of live birds in Suffolk had not been undertaken as "evidence of astonishing complacency".
Mr Miliband said he would provide Mr Ainsworth with details of the Suffolk tests, but he said: "All the scientific advice is that we have one of the most effective surveillance and testing schemes anywhere in Europe."
Drop in sales
Last week Bernard Matthews admitted to BBC East that at one stage sales had fallen by 40% after the bird flu outbreak.
The TGWU called on the government to pay compensation to the industry because of the drop in sales.
It said any compensation should include payments to the staff who were being laid off.
The 130 workers standing down will receive a one-off payment of £100 each from the company as well as some statutory payments, the TGWU said.
Chris Kaufman, national officer of the TGWU, said: "Industry will need the full backing of its government as it faces a challenging period.
"The government should also assist the workforce by ensuring that the benefits they are entitled to are processed without delay."
The H5N1 strain of bird flu was found at a Bernard Matthews farm in Holton earlier this month.
It was nearly identical to a strain found in Hungary, where the company has a plant which regularly supplied meat to its UK operation.