Coronavirus testing for health workers started in Belfast on Saturday just days before the expected surge of cases.
Staff were arriving at the car park of the SSE Arena throughout the day for appointments to be tested using kits from the diagnostic company Randox.
It came as the Ambulance Service announced a new protocol ahead of the peak of Covid-19 cases which is expected in the coming days.
A new level of escalation will include a specific Covid-19 protocol to categorise 999 calls.
It will involve specific questioning of patients for coronavirus symptoms so crews can prepare with the appropriate personal protective equipment.
“As the demand on ambulance services increases, this protocol also enables NIAS to ensure that all patients with immediately life-threatening and serious conditions, whether or not they are related to Covid-19, will be prioritised for the most immediate response,” the NIAS statement continues.
“Regrettably, it may be necessary to withhold an ambulance response to calls and deal with some calls through triage.
“These will be calls which have been assessed as less serious in nature and do not need an ambulance response.
“NIAS apologises to any patients who may find themselves in this situation but we would ask for your understanding in advance.
“These are exceptional circumstances requiring exceptional measures.
“NIAS will continue to monitor and review our response capacity and will react to any improvement in the situation without delay.”
The number of people who have died in Northern Ireland after contracting coronavirus has risen by eight to 56, health officials said on Saturday.
In their daily update the Public Health Agency said testing had resulted in 94 new positive cases, bringing the total number of confirmed cases in the region to 998.
The latest figures came after Friday saw the highest number of deaths in one day announced with 12.
So far Belfast has seen the majority of cases, following by the Lisburn and Castlereagh council area while Causeway Coast and Glens have seen the fewest.