More than 1,500 have contracted the coronavirus, with thousands more subject to quarantines.
In June, the districts of Gütersloh and Warendorf were placed under lockdown due to the virus, with residents of these regions banned from holidaying in other parts of Germany.
The employees, many of them from foreign countries, were forced to work and live in cramped conditions which experts think exacerbated the spread of the virus.
Ralf Stegner, from the Social Democrats (SPD) said Tönnies endangered his workers and broader society.
“There is real exploitation. It has a lot to do with the fact that we had a corona hotspot there,” Stegner told German tabloid Bild.
Stegner criticised Tönnies’ company’s request for state assistance due to a forced closure as a result of the coronavirus lockdown, implying that the only way the billionaire should be reliant on state funds is if he finds himself in prison.
He added: “Such a person does not need state help from taxpayers' money, he should be held responsible. Maybe he will end up in state food and lodging at some point.”
Stegner, who is the SPD parliamentary leader in the northern state of Schleswig-Holstein, said any access to public funds would be “outrageous”.
German Labor Minister Minister Hubertus Heil previously said the company should pay damages as a result of its conduct.
Reform of meat industry
Meanwhile, Germany has vowed to crack down on working and accommodation conditions at meat processing plants after a number of outbreaks in the country during the coronavirus crisis.
A draft law agreed by the government will force slaughterhouses to quit the practise of hiring eastern Europeans on short term contracts and will impose heavy fines on companies that fail to comply.
Trade unions say that the eastern Europeans are the victims of appalling living conditions at the mass accommodation provided for them by sub-contractors hired by the meat packing industry. Furthermore they lament a practise of meat companies contracting out work to subcontractors so that they cannot be held liable when abuses are exposed.
What was the cause of the outbreak?
More than 1,500 employees contracted the coronavirus at the Rheda-Wiedenbrück meat plant run by Tönnies, Germany's leading meat processing firm.
NRW Prime Minister Armin Laschet said it was the largest single outbreak of infections in North Rhine-Westphalia and Germany so far.
Of 6,140 Tönnies employees tested, 1,553 were confirmed as infected with coronavirus. The meat plant was closed for two weeks.
Many of the workers at the processing plant come from eastern Europe and have short-term contracts. There were concerns that people are living and working in cramped conditions which can fuel the spread of the virus.
On top of that, around 7,000 workers were placed under strict quarantine orders and unable to leave their homes.
Authorities put up fencing around residential buildings where workers lived and were distributing food.