The sorting office at Great James Street in Derry.
Postal services in Derry are expected to resume today.
Deliveries were disrupted yesterday after staff refused to enter the city's sorting office at Great James Street.
This was a result of the high number of Covid-19 cases that have been identified recently among the workforce at the sorting office.
It is understood that a number of other staff are also self-isolating.
The remaining staff yesterday said they did not wish to enter the sorting office until a deep clean had been carried out of the building and the postal vehicles.
Royal Mail said the clean was carried out yesterday and that services will resume today.
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