An investigation has been launched by the Department of Infrastructure into work permits for security staff at the airport.

It follows a check by the works permit division last Thursday when two security officers were found to have no permits.

Airport director Ann Reynolds said: ’I was informed there was an issue with work permits for our security contractor, which we are looking into, although I believe the work permit was restored last Friday.’

The affected staff went home of their own volition, concerned about working illegally.

A third person - a duty manager since June - also had no work permit.

He carried on working and got a permit to work as a security officer and the manager’s job has been re-advertised.

Two employees of Resource Security Services - which operates the security at the airport - contacted this newspaper and spoke anonymously, raising their concerns about a number of staffing issues at Resource.

Resource Security Services and the work permit division declined to comment.