The Public Service Association says it is concerned that job cuts at the Ministry of Justice will increase the workload of other staff.
The ministry has announced it will close one of its four district court regional offices by August.
Deputy secretary of operations Liz Sinclair says there could be between 20 and 30 redundancies, although it is too soon to confirm numbers.
Association national secretary Richard Wagstaff says courts are already struggling to cope with rising case loads.
Mr Wagstaff says the loss of jobs could mean remaining staff will have to pick up more work.
He says the Government has not kept to its promise of a cap on the number of state sector jobs.