Workers at a food processing plant in Dungannon have refused to start their shifts because of an "absence of social distancing measures", according to the trade union Unite.
It said around sixty workers at Linden Foods walked out on Friday morning demanding talks with management.
Unite regional officer Brian Hewitt said the company has provided no additional wash facilities and failed to stagger breaks.
Mr Hewitt said: "There have been ongoing issues between management and workers at Linden Foods over the issue of the absence of social distancing for workers on the boning line, in the canteen, changing areas and at entry and exit points."
He added that staff exhibiting symptoms of Covid 19 were still allowed to work.
In response Linden Foods said around 40 staff from its total workforce did not attend work on Friday morning.
The statement added: "We are adhering to government guidance and continue to actively take feedback from our teams on the implementation of the measures taken."
The company said it had implemented measures across all it's sites to provide a safe working environment.
These include new hand washing units, increased sanitising units, staggered breaks, new temporary changing facilities and carrying out temperature checks.
Earlier this week, there were walk-outs at poultry firm Moy Park in Portadown and the ABP food group in Lurgan over similar concerns around social distancing measures and sharing equipment.