Staff at the UK Border Agency are to vote on whether to take strike action in protest at the dismissal of a union representative.
More than 1,200 members of the Public and Commercial Services union at a UKBA site in Liverpool will be balloted on whether to launch a campaign of industrial action, which could start in mid-February.
The PCS claims one of its members was sacked last year after being targeted for his union activity.
A UKBA spokesman said "We want the PCS leadership to call off this groundless ballot.
"We have correctly followed disciplinary procedures in this case and industrial action will not change the outcome but will simply have an negative impact on the public."