More than 500 staff at courts in England and Wales will be balloted for industrial action due from Monday over Covid safety concerns.
Members of the Public and Commercial Services union at 12 courts will vote in the coming weeks on whether to launch a campaign of action.
The union is calling for courts to be closed, with critical cases conducted virtually.
The union said courts should only reopen when an impact assessment has been carried out, staff are tested regularly and increased safety measures are implemented.
Staff being balloted work in Birmingham Crown Court, Cardiff Crown Court, Highbury Magistrates Court, Isleworth Crown Court, Leeds Magistrates Court, Leicester Law Courts, Liverpool Law Courts, Manchester Crown Court, Snaresbrook Crown Court, Southwark Crown Court and Wolverhampton Combined Court.
PCS general secretary Mark Serwotka said: “Court staff have been working incredibly hard in this pandemic keeping the justice system running but they are deeply concerned for their safety.
“Management’s refusal to agree to our sensible proposals including holding critical cases virtually and mandatory Covid testing for staff, is what has led to this ballot.
“Strike action is always a last resort but if our members vote to walk out we will back them all the way until we reach a just and safe settlement.”
A Ministry of Justice spokesman said: “Throughout this pandemic the Government has been clear that justice must continue to be delivered for the public, victims and defendants.
“Every building we operate meets the Government’s Covid-secure guidelines, and public health experts have confirmed our arrangements remain sufficient to deal with the new strain of the virus.
“Positive test numbers are consistent with the wider community and it’s likely that the vast majority contracted the virus outside courts. It is simply untrue to suggest people are at an elevated risk of infection when at a court or tribunal.”
Union members being balloted work as ushers and other support staff.
