Workers at the DVLA are to be balloted for strike action over continuing coronavirus health and safety concerns at the Swansea site.
Members of the Public and Commercial Services Union (PCS) will vote in the coming weeks on whether to launch a campaign of industrial action.
The union has been pressing for on-site staff levels to be cut back following hundreds of coronavirus cases and the death of one employee.
Public Health Wales declared an outbreak at the driving agency's call centre in Swansea in December last year. More than 500 cases have been recorded at the site since September.
The Chief Executive of the DVLA has previously insisted that the increase in cases at the end of last year reflects an increase in the wider Swansea community and that all health and safety improvement advice from public health officials has been adopted.
PCS general secretary Mark Serwotka said: "It is a scandal that DVLA have insisted over 2,000 staff members come into work every day, despite having the biggest outbreak of Covid in an office workplace within the UK.
"Workers have expressed their real fear at going into work.
"Balloting our members for strike action shows the anger workers feel at their treatment and PCS will also support them in any individual claims they make to keep themselves safe."
Earlier this year, employees reported that they were being told to turn off their track and trace apps and that cleaning was "not up to the required standard" - something the DVLA have denied.
A Department for Transport spokesman said: "It is disappointing to see that staff at DVLA are being encouraged to carry out industrial action by the PCS. This action will only create unnecessary anxiety for those conducting critical work onsite.
"The health and safety of DVLA staff is paramount to us which is why rigorous protocols are in place, including strict social distancing between workstations and tightly controlled staff bubbles to minimise contact.
"These protocols are kept under regular review and the DVLA continues to take additional measures wherever possible to ensure the safety of its staff, including recently opening an additional office space and offering lateral flow testing to staff on site.
"All of this has led to a very low number of cases currently among staff."