Immigration officials employed by the UK Border Agency have voted for industrial action.
More than three quarters (78%) voted to strike over plans to merge the duties of immigration and customs staff, according to the PCS (public and commercial services union).
A two-day strike could begin on 5 August and the UK Border Agency has said that, should this happen, contingency plans would be set up to minimise disruption.
The dispute has developed over potential changes to working practices and shift patterns following the merger of immigration and customs staff that resulted from the creation of the UK Border Agency.
Alex Flynn, PCS national press officer, said the union had been holding talks with management and although members were keen to avoid inconveniencing the public they "want to continue doing the jobs they signed up for".