Tayside Contracts has been accused of gross negligence for insisting school catering and cleaning staff go into work this week.
Catering, cleaning and other facilities staff are continuing to work in schools, where children of so-called key workers are spending their days.
However, union bosses claim the number of workers expected far exceeds the number of kids that are in each school.
Helen Meldrum, Scottish organiser of the GMB said: “I can’t believe this but Tayside Contracts were still asking all Dundee based catering cleaning and facilities staff in yesterday.
“It seems to be gross negligence on their part to do this. Most of the schools have very few children in if any at all yet they are still herding people in.”
The staff concerned received a letter from managing director Iain Waddell advising them to continue to go into work.
However, Frank Reilly, head of human resources for the organisation, accused the union of causing “unnecessary worry and concern”.
He said: “Tayside Contracts has communicated to our employees and our recognised trade unions repeatedly that we will never ask our employees to carry out any tasks that put their health at risk.
“We have in place a generic risk assessment based on the advice of Health Protection Scotland, the essence of which is that no tasks will be carried out unless there are adequate hand washing facilities and where a minimum of two metres separation from colleagues can be maintained.
“If this cannot be achieved additional risk control measures such as the provision of masks and gloves are considered. Should there be a situation where potential risks cannot be adequately controlled then the work will not be carried out.”