NET bosses have issued a statement after it emerged that some tram drivers are self-isolating after they were contacted through the track and trace app.
Some services have been withdrawn in the day and delays have been reported across the network.
Because the number of workers isolating each day varies, services levels are under constant review.
A NET spokesman: “Like many other organisations, we have seen employees across the business being contacted through the government’s track and trace app, requiring them to self-isolate.
“Sensibly they are complying with these instructions and understandably, on some occasions, this is having an impact on employee availability and the staff rota, particularly when more than two or three people receive notifications over a short period of time or overnight.
“In response, we have temporarily withdrawn a small number of services during the day and adjusted the timings of others slightly to minimise waiting times between trams.
"This has been done to ensure we continue to deliver a safe and robust service to customers while following government guidance, as we have done throughout the pandemic.
“As the overall number of employees required self-isolating varies day-by-day, service levels are under constant review, and we would like to apologise to customers for any inconvenience and thank them for their patience and understanding.”
Meanwhile, a report signed off by Mike Mabey, NET's head of operations, has revealed that community protection staff have conducted 857 individual patrols on the network from February to May.
Some of the patrols were carried out in uniform and others in plain clothes - and staff spoke to passengers about wearing face masks and confiscated alcohol where necessary.
